North American Proboscideans and Dr. Chris Widga – Part 1

“Most zooarchaeologists are interested in the people, and they use the animals as kind of a tool for understanding butchering patterns or food ways or something like that.”

Dr. Chris Widga and I were in the midst of a great conversation about three recent papers he co-authored, paleontology, proboscideans, and the state of science today.

“I was always interested in the animals themselves,” he continued, “so when I got the position as a vertebrate paleontologist at the [Illinois State Museum], all of my friends who’d known me for years said, ‘well, that was a no-brainer for us. You were doing vertebrate paleontology all the time on Holocene bison. You never cared much about the people!’”

That beginning in zooarchaeology and the subsequent immersion in paleontology are what give him a unique perspective of the two sciences.  Or, as he himself explained: “I guess I kind of have this foot in both worlds.”

The two occasionally overlap.  In the paper published this past February in Boreas, “Late Pleistocene proboscidean population dynamics in the North American Midcontinent,” he and his colleagues take a closer look at what might have caused the extinction of mammoths and mastodons in what is now the middle of North America. Possible culprits include climate change, shifts in available vegetation, and predators (including humans).

Of the 627 localities included in this study, only 3 offer any kind of human association.  The authors state that these sites were “re-visited to ensure consistent taphonomic and zooarchaeological data,” and that, despite this, whether or not these specific humans and proboscideans interacted remains unclear.

“That’s a distinction I like to make as a paleontologist and a zooarchaeologist,” Dr. Widga offered. “Just because we have a couple of the sites with humans associated [doesn’t necessarily indicate that] humans actually hunted, killed and butchered those animals.  [Humans] may have scavenged them.  They may just simply be associated in these sites. And very few of those sites have been analyzed to the degree of detail that we really need to start teasing apart those issues.”

What he and co-authors Stacey N. Lengyel, Jeff Saunders, Gregory Hodgins, J. Douglas Walker, and Alan D. Wanamaker try to do, however, is take a deeper look at the late Pleistocene environment in which these proboscideans lived.  It’s exciting research: Rather than simply describing fossils discovered in the various US states and one Canadian province, they are trying to put them into context.  In other words, they are trying to understand the ecology of that time period and how that may have affected the megafauna living within it.

But it’s not an easy task.

“Ecologists can look at modern ecosystems and say, ‘Ok. This is what’s going on, and this is why we think that, and this is how we’re measuring it’ in great detail.  But extrapolating those same processes back into the paleontological record is often really, really difficult even with the best data set.

For example, “[w]e can observe boom-and-bust cycles in deer populations, in caribou populations, in musk ox and things like that. But when you try and translate that into the paleontological record, most of the time it’s really difficult because you simply don’t have the samples and you don’t have the time resolution.

“Even in our case, where we have really good samples and we have really good dates on our samples and we’re creating this chronological structure to kind of fit them in, it’s really difficult to translate those patterns into ecology.

“We can’t date a single mastodon any more precisely than about a hundred-year window.”

The fact that some of the ecological constructs used today in extant populations are controversial makes trying to apply such constructs to extinct animals that much more of a challenge.

“When even the ecologists can’t truly [agree upon] what’s going on, you have to navigate things very, very carefully.”

The amount of work put into this paper (work that has produced previous, subsequent and yet-to-be-published papers) is staggering.  Thanks to a National Science Foundation grant, Dr. Widga and Dr. Jeff Saunders—both previously at the Illinois State Museum—were able to visit an astounding number of museum collections in the Midwest and review their proboscidean fossils.

“We’ve [basically] spent the last 5 years in other people’s collections,” he explained. “It was fun because we visited a lot of collections that people don’t usually go to. About half of the data set comes from repositories that have fewer than five mammoths and mastodons.”

 

 

An inside look at the extensive fossil collection at the Indiana State Museum collection–one of the many collections visited by Dr. Widga.  In our conversation, he said, “The Indiana State Museum is a big dot on the map in terms of mammoths and mastodons, in part because of [paleobiologist Ron Richards’] work!”   This image was taken in 2005, picturing then Collections Manager Michele Gretna (currently Director of Archaeology); image courtesy Indiana State Museum and Historic Sites.

Another inside look at the Indiana State Museum collection; Preparator Elizabeth Scott after the reconstruction of the Kolarik locality mastodon tusks, 2014; image courtesy Indiana State Museum and Historic Sites

 

 

Their work involved the review of over 1600 fossils that currently reside in collections in Ontario, Canada, as well as in Arkansas, Illinois, Indiana, Iowa, Kansas, Kentucky, Minnesota, Michigan, Nevada, Ohio, South Dakota and Wisconsin.

“We doubled the number of known published sites for mammoths and mastodons in the Midwest.”

Information that they are willing to share with other scientists, as evidenced by the number of papers they continue to co-author.  Following the Boreas paper, Dr. Widga was part of another two papers published in March in Quaternary International and then in Scientific Reports.

Mammoth teeth take a leading role in the paper, “Reconciling phylogenetic and morphological trends in North American Mammuthus,” published in Quaternary International and co-written with Jeff Saunders and Jacob Enk.

“We’re starting to put out some of these ideas that actually put data onto these [traditional] species boxes that we like to put specimens into.  So that was one of the first steps into thinking about these things: more as morphologically variable populations rather than just trying to assign them to a particular species.

“A lot of times these studies kind of happen in isolation.  So the people that think about morphology, they’ll publish on the morphology and then post-hoc, they’ll say, ‘oh but this doesn’t agree with the genetics at all.’ Or the geneticists will publish on the genetics, but they don’t integrate any morphology.  So our point was to try and integrate both of them and see what they say. Can you use the genetics to kind of structure your interpretations of what the morphology means?”

The authors studied “M3s”—the permanent upper 3rd molar—of both female and male mammoths of various ages from museum collections and from previously published work.

Per Dr. Widga, this is the upper 3rd mammoth molar from Clear Lake Sand and Gravel Pit, Sangamon County, IL. One of his favorites from the ISM collection. It dates to the Last Glacial Maximum and had preserved DNA so is included in the Enk dataset; image and caption courtesy Chris Widga.

 

“Jeff [Saunders] and I would say, ‘this genetic information actually fits perfectly with our morphological information which suggests that there’s a lot of population overlap in between these normally well-defined populations.’ So in between Columbian mammoths in the Great Plains and woolly mammoths from the Great Lakes you have Iowa mammoths that show characteristics of both. And also they show characteristics of both in the same animal!

“That was kind of the impetus for the [Quaternary International paper]: to get that out there, show that you do get a lot of overlap in the morphology. It’s not just clean boxes of Columbian mammoths and woolly mammoths. And even pygmy mammoths overlap with Western Columbian mammoths! So that was kind of the point of the paper: to get the conversation going and make a first pass–a first attempt–to reconcile the two data sets.”

Following soon after the paper in Quaternary International, he was part of a remarkable group of proboscidean and genetic scientists whose paper The evolutionary and phylogeographic history of woolly mammoths: a comprehensive mitogenomic analysis analyzed 143 woolly mammoth mitochondrial genomes.

As Dr. Widga said with characteristic enthusiasm about his work in paleontology, “It’s always fun! There’s always a mountain to climb and a vista to see!”

*****

A Mammuthus columbi-sized THANK YOU to Dr. Chris Widga, who was remarkably generous with his time, with images to use and with answering my many, many questions (both for this blog and for my own proboscidean curiosity).  Speaking with him was delightful; he is an incredible ambassador for science in general!

Another sincere THANK YOU to Ron Richards for providing the great images of the Indiana State Museum collection. 

References:

  1. Widga, C., Lengyel, S. N., Saunders, J., Hodgins, G., Walker, J. D. & Wanamaker, A. D.: Late Pleistocene proboscidean population dynamics in the North American Midcontinent. Boreas. 10.1111/bor.12235. ISSN 0300- 9483.
  2. Widga, C., et al., Reconciling phylogenetic and morphological trends in North American Mammuthus, Quaternary International (2017), http://dx.doi.org/10.1016/j.quaint.2017.01.034
  3. Chang, D. et al. The evolutionary and phylogeographic history of woolly mammoths: a comprehensive mitogenomic analysis. Sci. Rep. 7, 44585; doi: 10.1038/srep44585 (2017).

Mastodon fossil at the Illinois State Museum; image courtesy of Chris Widga.

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Stegodon: Does this ancient elephant have origins in Asia?

So much has been said in recent years about the wealth of fossils in China. Almost all of it about dinosaurs: exciting new species, feathered fossils, nest upon nest of dinosaur eggs.  There is no doubt that China holds exciting clues to the history of our planet; one has only to wait to hear of the next discovery.

Within the past few months, yet another exciting find was revealed, but this time about a little known mammalian ancestor: Stegodon.

 

Stegodon by artist Hannah Stephens

Painting of a Stegodon by artist Hannah Stephenshannahleestudio.com.

 

The name Stegodon, to me, evokes ‘dinosaur’, not ‘mammal,’ but this was, indeed, an ancient animal.  Its fossils resemble those of other similar mammals, from mastodons to mammoths to today’s elephants.

 

 

Alexandra van der Geer - shrinking elephants

Figure 1: Reconstruction of four insular dwarf proboscideans with their respective mainland ancestors. Mainland proboscideans: 1, Palaeoloxodon antiquus; 2, Mammuthus columbi; 3, Stegodon zdanskyi [stegodon found in China]. Insular proboscideans: 4, Palaeoloxodon ‘mnaidriensis’; 5, Palaeoloxodon falconeri; 6, Mammuthus exilis; 7, Stegodon aurorae [a type of dwarf stegodon found in Japan]. Based on skeletons at Museo di Paleontología, University of Rome, Italy (1), American Museum of Natural History, New York (2), Taylor Made Fossils, U.S. (3), Museo di Paleontología e Geología G.G. Gemmellaro, Palermo, Italy (4), Forschungsinstitut und Naturmuseum Senckenberg, Frankfurt, Germany (5), Santa Barbara Museum of Natural History, Santa Barbara, U.S. (6), Taga Town Museum, Honshu, Japan (7). Photos 1–2, 4–7 George Lyras, photo 3 courtesy of TaylorMadeFossils.com, reproduced here with permission.

From The effect of area and isolation on insular dwarf proboscidea by Alexandra A. E. van der Geer et al; photo and caption courtesy of Dr. Alexandra van der Geer.

 

When Stegodon skulls with tusks attached have been found, many (but not all) of the tusks are close together–preventing the trunk (the ‘proboscis,’ from which this group gets its name; proboscis —> proboscidea) from hanging between them.

They lived in what is now Africa and Asia, causing continued debate over its place of origin. Until recently, the oldest known Stegodon fossil, a 6.5+ million-year-old partial molar from Kenya, was described by William J. Sanders in 1999.  That record changed this past December when Dr. Hong Ao and his colleagues published their results dating the sediment in the Lanzhou Basin, China, from which a number of fossils–including that of a Stegodon–were found.

And that Stegodon was found to be between 8 – 11 million years old.

 

GSA Geologic Time Scale - Neogene

Detail of the Geologic Time Scale, created by the Geological Society of America.  Stegodon is believed to have existed between the Miocene to the Pleistocene, a relatively small segment of time in Earth’s overall history, but still considerably longer than that of our own species!  (You can view the time scale in much better detail here.) 

 

The fossils of the Stegodon, along with at least 5 other species, were actually found in the 1980s by Professor Xing Zhang of Northwest University in China.  Given the length of time between the fossil excavations and the recent dating of these fossils, one might wonder why determining the fossil age took so long.

Dr. Ao, a scientist at the State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, and his colleagues state that western China does not have suitable material for radiometric dating, an oft-used method for this purpose.

When I asked why this was so, Dr. Ao replied by email, “Because volcanic activities are rare in western China during the late Cenozoic, it is difficult to find  in situ tephros or tuffs for radiometric dating (e.g., 40Ar/39Ar dating).”

Instead, they conducted a magnetostratigraphic study, one in which they determined the age of the rock through the polar reversal record.  Combining this with analysis of the fossils provided evidence that this Stegodon is 2 – 5 million years older than that of the Kenyan partial molar.

“We are indeed surprised by our dating results,” Dr. Ao continued, “which document that the Lanzhou Stegodon is the oldest Stegodon worldwide, although the Stegodon  fossil [was] not discovered by us. However, our dating results document it to be the oldest known Stegodon fossil.”

Dr. Hong Ao 1

 

Dr. Hong Ao 2

Dr. Hong Ao 3

Dr. Hong Ao 4

Images of Professor Yongxiang Li (from Northwest University) and his master student as well as several employed workers who helped to excavate mammal fossils, Lanzhou Basin, China; photos courtesy of Dr. Hong Ao.

 

indricotherine fossil

indricotherine fossil2

indricotherine fossil3

Images of indricotherine fossils found in Lanzhou Basin, China; photos courtesy of Dr. Hong Ao.

 

Dr. Ao himself has been working with fossils in the Lanzhou Basin for 5 years.  When asked how  he and his co-authors chose to work together on this recent paper, he wrote, “I have collaborated with them on broad subjects before, thus I [invited] them to join [in] this research.”

Finding information about this extinct species is difficult.  Unlike mammoths or mastodons, Stegodon does not appear to be a popular ancient animal.

Fortunately, Dr. Alexandra van der Geer–paleontologist, indologist, ethno-zoologist and author –has not only studied this species, she very generously made herself available for questions.  Currently, Dr. van der Geer is an Associate Researcher at both the National and Kapodistrian University of Athens and the Naturalis Biodiversity Center in the Netherlands. She is part of the Isolario project, a project that studies biodiversity and cultural evolution within an island context.

When I asked why there was such a dearth of information on Stegodon, she wrote, “We can think of several reasons for this.”

“First of all, stegodons typically are the elephants of Southeast and East Asia, where most countries did not have the resources and opportunities most Western countries had when it comes to scientific research and excavations. These activities are costly, and since they don’t have a direct use in the sense that they don’t advance the medical, technical or economic levels of a country, they have, understandably, a lower priority. Furthermore, because of this region, half the publications (especially before the 1990s or so) you can find are in Chinese or Japanese, which is not very helpful to the [English-speaking] world.

“Secondly, stegodons are forest elephants. Forest areas are very unlikely places for the long-term preservation of organic materials: everything is eaten, digested or otherwise broken down into smaller components in no time. The tropical (warm, humid) climate of these forests is not helpful either, as decomposition is much faster here. Stegodon remains only have a chance to be preserved when (1) they are covered fast, such as with river sediments, volcanic ashes etc., (2) or are in an oxygen-free environment, such as sunken deeply into a swamp, (3) or were deposited in a natural fridge such as limestone caves where they are gradually covered in clayish sediment or [travertines]. The same is valid for Palaeoloxodon, the Old World fossil elephant, but Europe has many limestone caves, which are excellent for preservation (for a nice [travertine]-preserved negative skull, see Stuttgart museum: skull cast SMNS nr. 32888 from Bad Cannstatt).

“As you can deduct from these preservation issues, it is more likely to find molars and tusks than skeletal material, which is much softer. The vast majority of proboscidean findings all over the planet consists of molars and tusks, and that is not for nothing. Inherently this means that there is much more information about their dentition and diet than about their bodies.”

I was interested in understanding why Stegodons are portrayed as hairless animals, so very similar to contemporary elephants.  Was this just an artistic guess?

“The hairlessness of stegodons is not an artistic guess but a scientific guess instead,” Dr. van der Geer answered.  “Very large animals with thick skins (pachyderms) in a (sub)tropical environment are unlikely to have a significant hair covering. Elephants lost their hairs secondarily. The information for hair growth is not lost, and baby elephants still have a thin, woolly coat. Woolly mammoths lived in the cold, temperate zones, and needed hair, so they were covered in a thick layer of hairs, and for this is evidence (mummies preserved in the permafrost), but the other mammoths (M. meridionalis, M. columbi, M. exilis, etc.), [did] not, and it’s generally assumed that they had a light coat fitting to the temperate zones.

“Tropical and subtropical stegodons almost certainly did not have any coat that’s worth mentioning. Stegodons of temperate zones, however, may have been more hairy. Indeed, the lack of hairs makes them look more like today’s elephants.”

 

Alexandra van der Geer - Stegodon ganesa-model-I.Vjdchauhan-SiwalikHills

Photo of the two life-size models of Stegodon ganesa;photo courtesy of Dr. Gerrit van den Bergh (University of Woolongong, Australia); special thanks to Dr. Alexandra van der Geer.

 

“Note, however, that the proboscis is carried very differently. Their tusks are set very close to each other, so the proboscis doesn’t fit in between as in modern elephants, Asian and African alike. This means that the mobility of their proboscis was more restricted, relative to their living relatives.”

 

Alexandra van der Geer - Flores-excavation-31-stegodon-florensis

Fossils of Stegodon florensis insularis, from Flores, Indonesia; photo courtesy of Dr. John de Vos (Naturalis, the Netherlands); special thanks to Dr. Alexandra van der Geer.

 

Alexandra van der Geer - stegodon-timorensis-mandible

Mandible (and holotype!) of  Stegodon timorensis; photo courtesy of Eelco Kruidenier (Naturalis, the Netherlands); special thanks to Dr. Alexandra van der Geer.  Anyone familiar with proboscidean teeth and jaws will recognize the similarities instantly.

 

But how do we know that Stegodon–a rather enormous animal–evolved into something smaller?

“[D]warfs and giants are relative. Something can be a dwarf, yet have a considerable size. When we speak of dwarf stegodons, we mean stegodons that are much smaller than their ancestors. For this, you have of course to have identical or otherwise similar elements from both the descendant and the ancestor in order to compare reliably,” she continued.

“The expectation is that dwarf stegodons must have existed on the islands, following the so-called island rule, according to which large animals get smaller in isolation. There is sound evidence that this rule still stands, and is even more pronounced for fossil species (see Lomolino et al., 2013, in Journal of Biogeography).

“Indeed, the many fossil molars from the Southeast Asian islands (‘Wallacea’) are all much and much smaller than the same molars from their mainland ancestors (see Van den Bergh, 1999). True, you first have to know what is the ancestor, and for this you need information about morphology, or how the molars, tusks, skulls and postcranial elements look like. After that, you compare the sizes.

“Note that if a molar is, for example, half the length of the same molar of its ancestral species, the body weight of that animal must have been a quarter of that of its ancestor! (the cubic law: linear reduction 50% means volume reduction 50% of 50%).”

Alexandra van der Geer - Flores-stegodon-florensis

Molar of Stegodon florensis; photo courtesy of Dr. Gerrit van den Bergh (University of Woolongong, Australia); special thanks to Dr. Alexandra van der Geer.  

 

“The most interesting dwarf stegodon is Stegodon sondaari, named after the Dutch palaeontologist Paul Yves Sondaar (1934-2003), expert in fossil insular mammals. This stegodon lived on the island of Flores about a million years ago, and weighted only about 15% of the weight of its ancestral species, S. elephantoides (see Van der Geer et al., 2016, in Journal of Biogeography, doi:10.1111/jbi.12743).

“Sondaar’s dwarf stegodon is not the smallest stegodon, that honour goes to the Sumba stegodon (S. sumbaensis), of only 8% of the original weight. Sondaar’s stegodon is interesting because it may have witnessed the arrival of early humans, possibly the ancestors of the Hobbit, or Homo floresiensis. Its fossils are contemporaneous with primitive lithic artefacts, dated to about a million years ago (see Brumm et al., 2010, in Nature 464, pp. 748–752).”

 

Alexandra van der Geer - Sumba-stegodon-sompoensis-holotype-in-Naturalis-Leiden-2

Molar (and holotype!) of Stegodon sompoenisphoto courtesy of Dr. Gerrit van den Bergh (University of Woolongong, Australia); special thanks to Dr. Alexandra van der Geer.  

 

“[R]ecently,” she concluded, “one of the island dwarf stegodons (S. timorensis of Timor) has been dated to about 130 thousand years ago (see Louys et al., 2016, in PeerJ 4:e1788). This excludes, according to the authors, an anthropogenic cause for its extinction, because humans had not yet arrived at the island.”

 

*****************

So many people helped with this blog post!  (But please remember that any errors are my own.)

Many, many thanks to Dr. Hong Ao (Dr. Ao Hong) from the State Key Laboratory of Loess and Quaternary Geology (Chinese Academy of Sciences) for his fascinating responses and the great images of fossil excavations in the Lanzhou Basin.  I am thrilled that he was willing to answer questions about his research and that of his colleagues! It was a great honor and a pleasure connecting with him!

I am indebted to Dr. Alexandra Van der Geer, who very kindly (and so very quickly–despite everything else she has going on!!) answered specific questions about Stegodon that I could not find anywhere else and who provided pictures of dwarf Stegodon fossils.  It was an equally great honor and pleasure connecting with her!

A mastodon-sized thank you to the amazing Dr. Katy Smith for providing needed and hard-to-find material on Stegodon fossils!

And an enormous thank you to artist Hannah Stephens for her depiction of a Stegodon as it may have appeared in life.  I am particularly moved by the warmth of its intelligent-looking eyes, and I love the tones within its skin.  I adore this picture.  I am grateful to have it in this post;  I am thrilled to have the actual painting hanging on my wall!  Please be sure to check out her artwork at: http://hannahleestudio.com or http://hstephens.blogspot.com

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References from Dr. Alexandra Van der Geer:

  1. Brumm A, Jensen GM, van den Bergh GD, Morwood MJ, Kurniawan I, Aziz F, Storey M (2010) Hominins on Flores, Indonesia, by one million years ago. Nature 464, 748–752.
  2. Lomolino MV, van der Geer AAE, Lyras GA, Palombo MR, Sax DF, Rozzi R (2013) Of mice and mammoths: generality and antiquity of the island rule. Journal of Biogeography 40, 1427–1439.
  3. Louys J, Price GJ, O’Connor S. (2016) Direct dating of Pleistocene stegodon from Timor Island, East Nusa Tenggara. PeerJ 4:e1788
  4. van den Bergh GD (1999) The Late Neogene elephantoidbearing faunas of Indonesia and their palaeozoogeographic implications; a study of the terrestrial faunal succession of Sulawesi, Flores and Java, including evidence for early hominid dispersal east of Wallace’s line. Scripta Geologica 117, 1–419.
  5. van der Geer AAE, van den Bergh GD, Lyras GA, Prasetyo UW, Due RA, Setiyabudi E, Drinia H (2016) The effect of area and isolation on insular dwarf proboscideans. Journal of Biogeography, doi: 10.111/jbi.12743

References used in this blog post:

  1. New magnetochronology of Late Miocene mammal fauna, NE Tibetan Plateau, China: Mammal migration and paleoenvironments; by Hong Ao, Peng Zhang, Mark J. Dekkers, Andrew P. Roberts, Zhisheng An, Yongxiang Li, Fengyan Lu, Shan Lin, Xingwen Li; Earth and Planetary Science Letters; 1o December 2015
  2. Oldest record of Stegodon (Mammalia: Proboscidea); by William J. Sanders; Journal of Vertebrate Paleontology; Vol. 19, No. 4, Dec. 13, 1999, pp. 793 – 797
  3. Fossil elephantoids, Awash paleolake basins, and the Afar triple junction, Ethiopia; by Jon E. Kalb; Palaeogeography, Palaeoclimatology, Palaeoecology; 1995, pp. 357 – 368
  4. The effect of area and isolation on insular dwarf proboscidea; by Alexandra A. E. van der Geer, Gerrit D. van den Bergh, George A. Lyras, Unggul W. Prasetyo, Rokus Awe Due, Erick Setiyabudi, and Hara Drinia; Journal of Biogeography; 11 March 2016.
  5. Magnetostratigraphy – concepts, definitions, and applications, by Cor G. Langereis, Wout Krijgsman, Giovanni Muttoni, and Manfred Menning; Newsletter on Stratigraphy, Vol. 43/3: 207–233, April 2010
  6. Mammoths and Mastodons of the Ice Age, by Adrian Lister, Firefly Books, 2014
  7. Mammoths, by Adrian Lister and Paul Bahn, University of California Press, 2007
  8. The Proboscidea: Evolution and Palaeoecology of Elephants and Their Relatives, Edited by Jeheskiel Shoshani and Pascal Tassy, Oxford Science Publications, 1996
  • Stegodontidae: evolutionary relationships by Haruo Saegusa, pp. 178 – 190, The Proboscidea: Evolution and Palaeoecology of Elephants and Their Relatives
  • Palaeobiogeography of late Neogene African and Eurasian Elephantoidea by Jon E. Kalb, David J. Froehlich, and Gordon L. Bell, pp. 117 – 123, The Proboscidea: Evolution and Palaeoecology of Elephants and Their Relatives

Meet Dr. Katy Smith – Mastodon Detective

If you imagine the Great Lakes region over 10,000 years ago, you might see large, hairy beasts with relatively straight tusks grazing around boggy areas or moving within dense forests.  Their fur and overall appearance might cause you to confuse them with woolly mammoths, but these are the mammoths’ shorter, stockier cousins.  And if any of them would let you get close enough to inspect their mouths, you’d see in an instant that their teeth are completely different than those of mammoths.

 

[image of contemporary boggy area in Alaska, courtesy Getty Images]

 

Whereas mammoths are believed to have eaten grasses and even flowers, mastodons needed teeth suited to the mastication of hardier stuff: shrubs, parts of trees, perhaps pinecones?   Mastodon teeth, with the bumps and ridges one might associate with carnivores, are easily recognizable as ‘teeth.’  Mammoths, in contrast, needed to grind food, producing teeth with spherical lengths of ridges across each tooth.

ISM - Mastodon tooth

 

[image courtesy of Ron Richards, Indiana State Museum, for this post: Mammoths and Mastodons in Indiana – Part 1.  Can you tell which tooth belongs to which species?]

 

ISM - Mammoth tooth

 

[image courtesy of Ron Richards, Indiana State Museum, for this post: Mammoths and Mastodons in Indiana – Part 1.]

And while woolly mammoths pervade popular culture and interest, there are some, like Dr. Katy Smith, Associate Professor of Geology at Georgia Southern University and Curator of the Georgia Southern Museum, who prefer their lesser-known cousins and have made fascinating contributions to our understanding of them.

Mastodon discoveries usually produce the fossils of a single animal, and rarely a complete skeleton. Rarer still, finding skeletal remains of multiple mastodons at the same site.

Such a unique discovery occurred in 2005, when more than 300 fossils were found in Hebron, Indiana.  Now known as the “Bothwell site,” it was originally going to be the location of the landowner’s pond.  Instead, Indiana State Museum paleobiologist Ron Richards and his crew uncovered bones that included numerous mastodons (Mammut americanum), giant beaver (Castoroides) and hoofed animals with even-toes (artiodactyls).

ISM - 2005 Bothwell Mastodon 2

 

ISM - 2005 Bothwell Mastodon 1

[images of the Bothwell site dig, courtesy of Ron Richards, Indiana State Museum, for this post: Mammoths and Mastodons in Indiana – Part 2.]

 

Four years later, the Bothwell site became the focus of Katy Smith, her dissertation, and two subsequent papers she co-wrote with Dr. Daniel Fisher at the University of Michigan.

But let’s take a moment to consider what paleontologists uncover. However rudimentary this may seem, it is important to note that bones are generally not discovered in neat order, intact and with each skeletal component attached where it would have been in the life of the animal.

Consider, too, that not all bones survive.  And those that do are often broken or in terrible condition.

So even at a site such as Bothwell, which produced lots of fossils, a paleontologist’s job is no less challenging.  The pieces of information are incomplete, mere clues to the animals that died there.

The questions, however, are profuse.

Why were so many animals found in that one spot?

If, as it is currently debated, mastodons shared behavioral traits with modern-day elephants, was this a family unit?

If so, was this group—like elephants–comprised largely of female and juvenile mastodons?

And why were other unrelated animals discovered among them?

Did a sudden disaster kill them all?  Were humans involved?

 

Embed from Getty Images

 

Sexual dimorphism is another way of referring to the traits that make an animal either female or male.  Some of us would assume, since mastodon pelvic bones were not among the Bothwell fossil assemblage, that the sex of these animals would remain unknown.

There were 13 mastodon tusks, only four of which were complete. And this, remarkably, is what prompted Katy Smith’s research.

“I wanted to know if I just had tusks, what can I do to figure out if I’m looking at a male or a female,” she explained by phone.

Katy Smith - measuring an African elephant tusk

 

[image of Dr. Katy Smith measuring an African elephant tusk in (what this author believes must be one of the greatest places on earth) the basement and fossil collection of the University of Michigan; courtesy of Dr. Katy Smith]

 

“Other people have looked at [sexual dimorphism], but I wanted to look at it specifically with the Bothwell mastodons, because they were inferred to be female, and female mastodons are less common in the fossil record than males.

“When I presented preliminary results from my research in a paleontology class, the professor said, ‘Why don’t you try multivariate analysis?’ And it just kind of spiraled from there.”

Multivariate analysis,’ as the name implies, means using more than one type of measurement or observation towards a hypothesis.  In other words, rather than simply using size as a determination of sexual dimorphism, applying numerous methods and statistics that support or disprove it.

Already, the amount of information scientists have pulled from tusks alone is fascinating.

Tusks are teeth.  They are described, in Dr. Smith’s dissertation as “hypertrophic incisors.” And, unlike human teeth, they continue to grow the entire life of the animal. So where we can simply look at a human tooth and know immediately whether it is from an adult or a child, the same cannot be done with tusks.

What their hardy structure records includes the age of the animal, growth in winter or summer months each year, their overall diet, and periods of nutritional stress.  (As described in an earlier post, Proboscidean molars can even provide details regarding where they roamed during life.)

But much of this information can only be gleaned from well-preserved, intact tusks, as well as from cutting into and examining their chemical composition.

“If you don’t know what the sex of the animal is before you look at tusk microstructure,” she said, “it can be hard to interpret what you’re looking at.”

Part of what Dr. Smith hoped to discover were similarities in the tusks where sex and age had already been determined.  If certain structural elements were the same across female mastodon tusks, such that they tended to differ from male mastodon tusks, this might help determine sexual dimorphism in future tusk discoveries.

She also hoped to discover any similarities between the tusks of extant elephants and mastodons.

Katy Smith -longitudinally bisected tusk

 

[image of longitudinally bisected tusk, courtesy of Dr. Katy Smith] 

 

Thus, she studied and measured tusks of both species from numerous museum collections. (Asian elephant tusks were not used, as female elephants of this species tend to have either tiny tusks or no tusks at all.)  She rather amusingly refers to the approximate amount of tusks involved as “5,000 pounds of tusk.”

Her dissertation and the two papers describe the type of analysis performed in detail.  Among them were canonical variates analysis (CVA) and discriminant function analysis (DFA).

“Fortunately, we didn’t have to cut into the tusks to do those measurements. You just insert a stiff wire into the pulp cavity.”

“We think about tusks sometimes as stacks of sugar cones, because they actually grow in a kind of [layered] cone structure. So you think about one sugar cone, and then you put another one inside that one and then another one inside that one and so on and so forth. And the last sugar cone is empty. There’s nothing in it. That represents the pulp cavity.”

“[Analyzing the] pulp cavity is probably one of the best single measurements that you can use to distinguish between male and females. [I]n females, that pulp cavity will terminate before the gum line, and in males, it will terminate after the gum line, closer to the tip.

“This is something that we saw in almost every mastodon. So it was kind of cool.”

 

Katy Smith - female mastodon

 

[image of female mastodon skull and tusks, courtesy of Dr. Katy Smith]

 

“If we could have cut every tusk, I would have,” she admitted, and laughed. “But it was a matter of collecting these measurements at different museums. And so I would just go there and collect all of them, and that was how we’d get the pulp cavity depth.”

“I’ve always been interested in paleontology,” she said when I asked her how she got started.

“I’m one of those kids who just never grew out of it. My parents used to take me to the museum all the time, and I used to spend hours and hours staring at the dinosaur dioramas there, just loving it.  I told my kindergarten teacher I wanted to be a paleontologist. I never changed! My 5-year-old self grew up and became a paleontologist.”

But her interests moved away from dinosaurs when she realized that their fossil record in Wisconsin, her home state, was rare to nonexistent.

After all, she said, “I started just wanting to explore what was underneath my feet.”

It wasn’t until grad school at Michigan State, where she met the late Dr. Alan Holman, that she realized her passion for mastodons.  His own interest in the species was infectious, and it was through him that she learned of the numerous mastodon (Mammut americanum) fossil discoveries in the area.

“Wow!” she said, recalling her initial reaction. “There are over 300 mastodons in Michigan. This is exciting!”

Katy Smith - male mastodon

[image of male mastodon skull and tusks, courtesy of Dr. Katy Smith]

Not surprisingly, she did her PhD work at the University of Michigan, home to Proboscidean expert Dr. Daniel Fisher, who was her advisor.

“I wanted to work with him,” she explained, “because I wanted to continue working on mastodons, and he had a couple of ideas for projects. One of them included this assemblage of mastodons from Indiana, which were—supposedly—all female.”

What she discovered regarding the Bothwell site is both thought-provoking and fascinating:

  • 8 tusks were determined to be female; the other 5 are unknown
  • the ages of the mastodons range between 19 and 31 years old
  • there is evidence that at least one juvenile might have been among them (a “juvenile tooth crown” was found)
  • given that two mastodons died in winter, and another two died either in late summer or early autumn, this indicates that the collective deaths of these animals didn’t happen at the same time (hence, not a single event)
  • none of the mastodons appeared to be under nutritional stress when they died
  • members of a family unit would be expected to have the same “isotope profiles”–chemical signatures in their teeth–but these do not

Based on the evidence provided, Dr. Smith wonders whether these animals were part of a meat cache for humans (members of the Clovis culture) that co-existed at that time.

But perhaps the single most remarkable result of her research is helping other paleontologists–who often have nothing more than a single tusk–determine the sex of that animal using her different types of analysis.

Prior to her dissertation, only one female mastodon tusk had been analyzed for growth rate.  To date, I am unaware of any other publication (paper or book) that helps detail the sexual dimorphism in mastodons by tusks alone.

When I remarked upon this, I asked her if others had cited her work.  Her response, after stating that others had, was equally fascinating to me.

“It’s always the hope as a scientist that you’re contributing in some way,” she said, “and you know that you’re contributing if somebody else is using what you’ve done.”

 

An enormous and sincere THANK YOU to Dr. Katy Smith for her generous and fascinating answers to my many questions, her gracious help when I had trouble understanding certain points, and for being so much fun with whom to connect! I cannot express how much I wish I could attend her classes, nor how fascinating I found her dissertation. I am profoundly grateful that she shared it with me!

A sincere thank you to my Dad, as well, for helping me understand tooth components (i.e.: dentin, cementum)!

**A quick reminder that I am neither a scientist nor a paleontologist, so any errors in this post are my own.

Bothwell Mastodont Dig, courtesy of Indiana State Museum; many thanks to Bruce Williams and Leslie Lorance!

—————

References:

 

Other references:

 

Cohoes mastodon size comparison

[image of sign in the NY State Museum illustrating the size difference between an extant elephant, a woolly mammoth and the Cohoes mastodon; picture taken by the author]

NH State Fossil? – Part 1: Interview with Thom Smith

In the Fall of 2013, Thom Smith and his 3rd grade class in Bradford, NH began their quest to create a State Fossil.  After much research and consultation with local paleontologists, Mammut americanum (a type of mastodon that most likely resided in NH) became their fossil of choice.  They were finally able to present their testimony to a committee within the NH House of Representatives this past February.

The story does not end well.

And it is a story that did not get as much attention as another proposal for a State Raptor proposed by 4th graders from a different NH town.

Rather than begin the story with my version of events, I wanted to let Thom Smith and these marvelous students speak for themselves.

Below is the initial Q&A exchanged between Thom Smith and me this past January.

NHSF - Class

[image of Thom Smith with his students and Rep. David Borden, the first NH legislator to take an interest in the bill, courtesy of Thom Smith]

1. How do you discuss fossils with your students?

Thom Smith: Instruction of fossils is centered on the idea that discovering fossils is equivalent to discovering clues about our past and our planet’s past.  Fossils are clues that help us look into the lives of ancient animals and plants.  Students become excited when they discover that paleontology is not just digging up old things, but about being a detective looking for clues that will help tell us the history of our backyard’s past.  We delve further into fossils by learning about the four main types of fossils, as well as by participating in a “mock” paleontology dig on our school’s fitness and nature trail. 

2. How did you (or do you) learn about fossils/paleontology?

Thom Smith: I initially learned about paleontology in elementary school as well.  To be honest I do not remember any further education in paleontology beyond that point – except perhaps teachers occasionally touching upon paleontology matters in other science classes.  I currently learn about fossils by reading up on any current event article that comes to light in the news, or by reading about recent discoveries in magazines or online. 

3. What was it about this class that inspired you to try to have a state fossil created in NH?

Thom Smith: It was a shared inspiration, and honestly, it was my students that originally came up with the idea.  When studying fossils my students often discover through readings and research of their own that New Hampshire does not have a state fossil.  This past year was no different, and when they became discouraged at that fact I asked them if they wanted to try and do something about it.  We had just been involved on a unit of study on citizenship, and I thought it might be a good opportunity for them to see what speaking up for their concerns as citizens might do.  As a third grade teacher, I also get the privilege of instructing our students on the New Hampshire state “officials”.  Every year students become greatly interested in learning about the ladybug, the Karner Blue butterfly and the purple finch.  I also encouraged my students to try to have a state fossil declared in New Hampshire because I knew it would help increase student interest in paleontology and the importance of learning about our state’s ancient past if a bill was to become law. 

4.  Have you had any experience with legislation before? (How have you found the process so far?)

Thom Smith: I have not had any experience with legislation before, yet the process so far has been very educational and encouraging.  Representative David Borden, who was the first state representative to offer our class his assistance, has been incredible.  He is a kind, sincere individual who really cares about our state’s youth and education.  He has gone to great lengths to encourage and educate our school’s students about state legislation, and has done so with a humble and generous attitude.  He understands that this quest for a state fossil is not just because some students in a small town in New Hampshire want one, but because these students who wish to have a voice have good reasons for their request and need supportive adults to help them.  The process of legislation takes a lot of time, but I think it is understandably so, at least in this circumstance.

 

5. The Concord Monitor article indicates that you connected with Dr. Gary Johnson at Dartmouth and Dr. Will Clyde at UNH. What prompted you to connect with these two people? What have you learned from them?

Thom Smith: The class initially needed advice on discerning which fossil they believed would be the best fossil to represent our state.  I connected with Dr. Will Clyde at UNH because the class watched a news clip on WMUR that featured Dr. Clyde providing his expertise.  I connected with Dr. Johnson because I searched online for other experts on fossils from New Hampshire and discovered that his sedimentary geology field of study led him to the discovery of fossilized dinosaur footprints.  Both professors were immediately helpful and encouraging.  We learned that New Hampshire is not a good state in searching for fossils because of its granite make-up, but that fossils have been found in NH, including brachiopods, mammoth and mastodon fossils.  The mammoth and mastodon fossils had been found more recently, including by fishermen off the coast of Rye.  We more recently learned of support for our classes’ request from Professor of Geology Wallace Bothner at UNH as well.

6. Did your students think anything other than a mastodon should be the state fossil?

Thom Smith:  I found the decision to determine what fossil should be our state fossil another good lesson in citizenship responsibilities. Our class made a chart with brachiopods, mammoths and mastodons, and in each column we wrote down facts about each fossil and how it related to our state.  We discussed the possible “candidates” for a couple of class sessions then held a big vote.  The mastodon won unanimously for a variety of reasons – ones we outlined in a letter that we sent to state representatives asking for support.  Those reasons included:

  • This fossil was found recently off the coast of New Hampshire
  • This fossil is an official state fossil in only one other state
  • Two well-respected paleontologists from New Hampshire suggested it as a possible official state fossil
  • This fossil connects our state’s present (New Hampshire’s fishing industry) to our state’s past
  • This fossil is a piece of our state’s ancient history that we should recognize, and as an official state fossil has the potential to encourage others to learn about our state’s ancient past
  • Our surrounding states have state fossils but New Hampshire does not

 7. Do they understand what a mastodon is?

Thom Smith: My students understand that the mastodon is an extinct, shaggy-haired elephant-type creature, similar to the mammoth except often smaller, and with shorter legs and flatter heads.

Cohoes mastodon

[image of Cohoes mastodon at the NY State Museum in Albany, picture by the author]

Indiana State Museum - Ice Age depiction

[painting of mastodons from an exhibit at the Indiana State Museum, courtesy of the Indiana State Museum for this post]

8.  Have they seen the mammoth tooth at the Rye Public Library?

Thom Smith: We have yet to see the mastodon tooth (as well as the mammoth tooth) that were found off the coast of Rye, but hope to soon!  Dr. Will Clyde has seen the mastodon tooth and it is one in excellent shape.   The interesting connection to Rye is that our class also learns about the rocky shore each year and visits Odiorne Point, near the location of where the mastodon fossil was found.  Last June Representative Borden and his wife met us there on our class field trip – it was a great experience.

9. What can people do to help (if anything) with the establishment of a state fossil?

Thom Smith:  Advocate for it.  Publicize the possibility – make it known that this legislation is occurring now and that the more support we have the less likely our students’ bill will be dismissed.  Blog about it (like you are doing), post it on social media, email the possibility of a state fossil to friends and ask them to support the endeavor.  Contacting state legislators is incredibly easy – they are often just an email away, and many are ready and willing to hear your thoughts and voice your opinions in the state house.  The first committee hearing on the possible establishment of a state fossil is January 27th*, and we hope there are more that lead to this LSR becoming a state law.

[*This date was pushed to February, due to inclement weather in NH at that time–author’s note.]

10.  Are there any questions I haven’t asked that you think would be important for people to know?

 

Thom Smith: I would want everyone to know that this request for an establishment of a state fossil was made by students who had a genuine, valid concern and had the motivation to do something about it.  This request was to change our state’s history so that others might learn more about our state history – its ancient history.  It may be debated as to whether or not the mastodon should be considered our state’s fossil, and a healthy debate would be fine, but we would not want our students’ quest to be lost in arguments that could go round and round when the request for a state fossil is not just about what the fossil should be, but more importantly why there should be one: having a state fossil would result in a lot of positives, including an increased interest in paleontology at a variety of levels, particularly New Hampshire’s youth.

NHSF - Rep Borden and Thom Smith

[image of Rep. Dave Borden and Thom Smith at Odiorne Point State Park, courtesy of Thom Smith]

You can read more detail about the events leading up to this past March at Thom’s blog: https://thirdgradesmith.wordpress.com

Exciting New Info About Mastodons and Humans – Yukon Paleontology, Part 1

“Good morning!”

It’s not just a greeting; it sounds like a proclamation.

The voice on the other end of the phone is deep, melodic, and—as our conversation progresses—punctuated with moments of laughter.  We have been discussing paleontology in the Yukon, and with each new detail, I begin to wonder why this territory is not making regular international headlines.

Dr. Grant Zazula’s work is fascinating, and it is neither a short phone call nor the only communication we’ve exchanged. And yet, it is all that I can do not to encourage him to keep going, long after social decorum dictates that he has been more than generous with his time.

Dr. Zazula and mastodon leg

[image of Dr. Grant Zazula with a mastodon ulna, part of the Earl Bennett mastodon, courtesy of the Government of Yukon]

Dr. Zazula is the Yukon paleontologist, a job that has only existed since 1996. His own tenure began in 2006.  With an office in Whitehorse, the capital of the territory, his work oversees an expanse of Canada that abuts Alaska.  It is a land of dramatic beauty, where colors dance in the sky and mountains tower in silent grandeur.

Embed from Getty Images

His most recent paper, co-written with 14 other people, made news throughout the world and continues to attract media attention. In it, the scientists present data that completely overturns previously believed information about extinct animals and the impact that humans may or may not have had upon their survival.

“[T]here were two radiocarbon dates in the literature from Yukon mastodons,” he explained in an email. “One that was ~18,000 and the other 24,000 years old.”

“Based on analysis of the paleoecology, that was a time when steppe-tundra grasslands covered Alaska, Yukon and Beringia. There were probably no trees, few shrubs and almost no standing water. It was very cold and, especially, dry. This seemingly is not good mastodon habitat. So either the dates were incorrect, or our understanding of mastodon ecology, behavior and adaptations need[s] to be revised.”

Various species of mastodon once existed throughout the world.  Although their fossils look elephantine, they are not believed to be direct ancestors of today’s elephants. They are, however, part of the same umbrella mammalian group: the Proboscidea (so-named for the trunks possessed by many—but not all–of their members).  In North America, that group contained the American mastodon (Mammut americanum), the woolly mammoth (Mammuthus primigenius), and the Columbian mammoth (Mammuthus columbi).

Cohoes mastodon

 [image of the Cohoes mastodon, NY State Museum, Albany; taken by the author]

Mastodons tended to have straighter tusks and were shorter than their mammoth cousins. They also ate hardier vegetation, food that required a much different tooth structure than mammoths.

ISM - Mastodon tooth

[image of mastodon tooth, courtesy of the Indiana State Museum]

ISM - Mammoth tooth

[image of mammoth tooth, courtesy of the Indiana State Museum; for more info about the differences between mammoths and mastodons, see this post.]

Parts of Siberia, Alaska and the Yukon were once connected in an area known as “Beringia.”  The Bering Strait did not yet exist, enabling animals and eventually the first humans to cross into our continent.  It is believed that humans arrived in what is now North America about 14,000 years ago.

And this is where the research of Dr. Zazula and his colleagues becomes particularly important.

Prior to their paper, one theory to mastodon extinction laid the blame upon first humans: it was proposed that they overhunted these animals.

Sampling 36 fossils and presenting 53 new radiocarbon dates, Dr. Zazula and his colleagues found that mastodons within Alaska and the Yukon were much, much older than the originally published dates.  In other words, their research suggests that mastodons from what was once Eastern Beringia were no longer present when the first humans appeared.

The path to this remarkable research did not happen overnight.

The foundation appears to have been laid by two different events: by the chance meeting of Dr. Zazula and a gold miner, and later, by the PhD work of a graduate student.

If one reads the acknowledgements on the aforementioned paper, Dr. Zazula references Earl Bennett as both the donor of a partial mastodon skeleton and his inspiration to learn more about mastodons within the Yukon.

“Earl is a great Yukoner,” Dr. Zazula wrote when asked about this. “He mined for gold underground in the winters with a pick and shovel, decades ago. He worked on big gold dredge machines. And, he loves paleontology.

“While mining, he made collections of Ice Age bones that were just left around the mining camp or were encountered while mining. He eventually amassed an amazing collection.

“In the early 1970’s a gold dredge on Bonanza Creek hit a skeleton of a mastodon. An incredibly rare find! Someone collected it and was looking to sell it. So, Earl bought the skeleton just to make sure that it never left the Yukon. He had it in his garage for decades.

“One day a mutual friend introduced me to him in a coffee shop, about a year after starting my job [as the Yukon paleontologist]. He said that he had a mastodon skeleton and wanted me to see it. I ‘corrected’ him, saying that it was more likely a mammoth, because we almost never find mastodons in the Yukon. He assured me he know the difference and said he would see me tomorrow at my office.

“The next day he backed his truck up and in it was a partial mastodon skeleton. I couldn’t believe it. There were several postcranial bones, some vertebra, scapula, parts of the skull and parts of the mandible with teeth. It was amazing. I wanted to find out how old it was, and that was one of the inspirations for this project. Earl is a good friend now and big supporter of our research.”

Bennett mastodon skeleton

[Paleontologist Grant Zazula with a partial American mastodon (Mammut Americanum) skeleton found on Bonanza Creek and donated to the Yukon fossil collection by Earl Bennett, from Ice Age Klondike, courtesy of the Government of Yukon]

That partial skeleton was indeed one of the many fossils sampled for the paper.

Dr. Jessica Metcalfe, one of the co-authors, also prompted this research when conducting work for her PhD.

“[S]he was doing a project looking at stable isotope ecology of mammoths and mastodons in various places in North America,” said Dr. Zazula.

Jessica Metcalfe with mammoth bone

[image of Dr. Jessica Metcalfe with mammoth bone, courtesy of the Government of Yukon]

Her work included Yukon fossils that were sent to the lab at the University of Arizona to be radiocarbon dated.   Those dates turned out to be older then 50,000 years old.

“So that’s what got me thinking,” he continued, “‘well, maybe those original published dates are wrong.’”

“The first step was to re-date [the specimens that had produced the original published dates]. The new dates turned out to be >50,000 years. So we knew there was a problem with the previous dates. We figured then we should date as many as we could get our hands on.”

This lead Dr. Zazula to connect with Dr. Ross McPhee, another co-author.

“I got in touch with him early because he oversees collections at the American Museum of Natural History, [and] he has a big interest and lots of experience working on Ice Age extinctions. [H]e’s an excellent writer and really kind of kept us going with some of the writings. He was really integral to keeping things together.”

The paper eventually involved a total of 15 people.

“I feel pretty strongly that if you worked on it and contributed to it, then you should be considered an author,” Dr. Zazula stated.  “So it ended up being a long list.”

One of the first aspects their paper addresses is the reason behind why the original published dates are incorrect: the dating analyses were contaminated by fossil conservation methods.

“Humic acids in soils can be absorbed by the bones and teeth and chemically bind themselves to the collagen,” he wrote, explaining further. “So, modern ‘young’ carbon in those acids basically contaminates the ‘old’ collagen in the ancient fossil. And, it can be tricky to remove.

“The same with consolidants in museums. Varnish, glue, and other substances to preserve fossils can be absorbed into the bone and chemically bind with the collagen in the bone. These substances probably contain young, modern carbon which messes up the radiocarbon dating measurements.”

When asked whether museums continue to use the same preservation products that contaminated the dates, he wrote, “Yes, for sure. The thing is now museums keep better records of what they use. Many of the fossils we dated were collected in the 1940’s or at least several decades ago. Museums were not that vigilant about keeping detailed records on those things then. Also, they seemed to put preservatives on everything. Now, at least if we know what was put on it, the chemistry can by developed to remove it. Most of the common preservatives now are soluble in alcohol or acetone and can be dealt with. The problem is when they are unknown.”

We discussed this further by phone.

“One thing about Alaska and the Yukon,” he said, “is that the Ice Age bones that come out of the ground are so well preserved because of the permafrost. In other localities, say, the deserts of the American Southwest or the Great Basin or the Plains, where bones have been out in the sun and [are] dry and hot, they [sometimes] fall apart really easily when they come out of the ground. They need to be glued and consolidated with these various types of museum products.

“So you kind of have to weigh the different values.

“Say if it’s a specimen that’s already been radiocarbon dated, and it starts to slowly disintegrate, well, then you kind of have to intervene or else you’re just going to end up with a box of dust and broken bone. You have to decide whether the importance is more with display or preservation of the morphology versus needing to radiocarbon date or other types of analysis.

“[Y]ou have to look at the pro’s and con’s of whether the sampling [for radiocarbon dating] will ruin the specimen or not, and what is the potential information that can be gained by doing it. To me, I feel that having a research collection [in the Yukon], it’s all about research and learning new things from these specimens.”

Ultimately, I wondered whether Dr. Zazula expected the results he and his colleagues uncovered.

“I wasn’t quite sure,” he answered. “I had the gut feeling that these previously published radiocarbon dates were probably wrong. It didn’t make a lot of sense ecologically to have mastodons living in the far North when it was seemingly habitat they couldn’t live in: habitat with grassland and cold, dry steppe tundra conditions, no trees and very few shrubs.

“But there [was] also a part in the back of my mind that thought, ‘well, if those [previously published dates] were right, that’s maybe even more interesting because they are telling us something about mastodons and their behavior and their adaptations that we didn’t know before.’”

————

It was a great honor and pleasure to connect with Dr. Grant Zazula! Not only patient with my myriad questions, he is an adept and fascinating ambassador for the Yukon. A Mammuthus columbi-sized thank you to him!

A Mammuthus columbi-sized thank you to Dick Mol, as well, who is the reason behind this post!

Dick Mol with horse skull

[image of Dick Mol with fossil horse skull, found near Dawson City, Yukon; courtesy of the Government of Yukon]

Yukon Paleontology Program: http://www.tc.gov.yk.ca/palaeontology.html

Articles and publication referenced:

 

Listen to Dr. Zazula discuss his paper on the CBC’s Quirks & Quarks: http://www.cbc.ca/radio/quirks/quirks-quarks-for-dec-6-2014-1.2864605/mastodons-made-an-early-exit-from-the-north-1.2864634

 

Dr. Brooke Crowley – Secrets Revealed from Mammoths & Mastodons in the Cincinnati Region

It may seem unlikely to uncover details about what an animal ate thousands of years after its extinction, absent of so much of the flora and fauna that co-existed with that animal.

It might seem even more improbable to illicit that information from fossilized teeth alone.

And yet, this is exactly what Dr. Brooke Crowley and Eric Baumann of the University of Cincinnati have done.

Brooke and Eric Baumann on Kardung La

[image of Eric Baumann and Dr. Brooke Crowley on Khardung La, India; courtesy of Dr. Crowley)

They sampled molars from eight different mammoths and four mastodons, each with a known provenance in the Cincinnati region. Analyzing stable isotopes within each tooth provided information not only about each animal’s diet, but also its habitat.

“Isotopes in our tissues,” Dr. Crowley, Assistant Professor of Quaternary Paleoecology, explained in a phone interview, “are environmental integrators.”

“What we like to say is that isotope values in an animal’s tissues can tell you something about its life. That could be the diet, it could be the environment the animal inhabits, or, in the case of strontium, it could be the actual locality where it lives.”

Over the past 30 years, studying stable isotopes has become an increasingly popular method of understanding both paleontological and archaeological finds in more depth.

These chemical signatures reveal details incorporated within the body over its lifetime and remain in its bones past its death. In other words, what one eats and drinks leave traces of elements that point back to that very same diet and to the region from which one drank water. That organic material has footprints, and scientists—using mass spectrometers and other types of analysis—can read and interpret them.

Remarkably, these chemical footprints remain, even after thousands upon thousands of years. And teeth, with their sturdy crystalline structure, seem to offer reliable stable isotope data.

Dr. Crowley and recent graduate Eric Baumann described their research in a paper to be published in Boreas. Carbon isotopes revealed broad information about what these twelve proboscideans ate; strontium and oxygen isotopes uncovered the region and climate in which these animals lived.

They began their research expecting to uncover that the two species were nomadic, that their teeth were discovered in areas geographically distant from their place of origin. They also expected that mammoths and mastodons ate different types of vegetation.

While their research confirmed the different diet, it provided surprising results for habitat: with the exception of one mastodon, all of these animals actually lived and remained within the Cincinnati region.

In response to why they originally thought these animals might be nomadic, Dr. Crowley pointed to the behavior of existing species.

“Most large animals aren’t sedentary.”

“In general,” she explained, “big creatures move a fair amount; they have large stomachs and they eat a lot of food. And there may be different reasons for moving. It could be a dietary need, it could be there’s some particular nutrient in the soil that they want from time-to-time, or there may be a particular region they like for birthing or mating.”

We see this today in humpback, gray and blue whale populations on either side of the North American continent, migrating from warmer regions in the ocean to colder regions thousands of miles north.

“African elephants, in particular, are typically very destructive by nature. They are what we call ‘environmental engineers.’ Their behavior changes the environment around them.”

Perhaps the most notable affect elephants leave in their wake are the trees they knock down. Consider, too, that elephants eat 160 – 300+ pounds of vegetation a day per elephant.

“[T]hey heavily modify an area. Then they move and modify another area. And they typically have pretty large home ranges. Some populations seasonally migrate from one place to another; others are just more continuously on the move.”

Embed from Getty Images

But, she cautions, “we can’t necessarily use that information to interpret the behavior of extinct species. They’re not necessarily that closely related. But it is something we have to go on.”

In their research, the authors include data from water samples taken from rivers and creeks in Ohio and Kentucky.

What, one might wonder, do modern-day water samples have to do with ancient teeth and their composition?

Strontium within water reflects the geology from which it came. This information is stored within teeth, thereby leaving yet more footprints the scientists can interpret.

Of the types of isotopes analyzed, Dr. Crowley explained that “[a] lot more work has been conducted on carbon and oxygen. So we didn’t really need to establish a local baseline for either of those two isotopes. But strontium’s a little less studied, and we didn’t know what sort of regional variability to expect.

“Without any comparative baseline, it’s hard to interpret what strontium in the animals might mean. We could say, ‘well, they’re all really similar’, but if we didn’t really know what to expect for this region, we wouldn’t know if they’re similar to the region or if all of those animals may have come from somewhere else. So we needed to establish a local baseline.”

In other words, they needed to understand the chemical signatures within local water in order to see if they matched the chemical signatures within these teeth.

“[This is] the first step,” she continued, “in what will hopefully be a long-term research direction: thinking about North American fauna and ecological change over time here on our own continent.”

When asked if this meant she would study other extinct animals or continue researching mammoths and mastodons, her response was “potentially both.”

“Currently I’m [working on a] project using strontium isotopes to look in a little more depth at particular individuals.”

Brooke and a bison scapula

[image of Dr. Brooke Crowley with a bison scapula; courtesy of Dr. Crowley]

She referenced a mastodon from Michigan as an example.

“[W]e’ve sampled little increments of his tusk to see how he moved during his lifetime.”

“One drawback of teeth,” she mentioned, “is that they just give you a relatively brief snapshot in time, whereas a tusk gives you a continuous record of an individual’s life.”

But she is equally interested in what she described as “big-scale patterns” of behavior across various species. And in this research, ‘behavior’ refers to details about their diet, and whether specific species roamed or remained in a specific region.

“If there is any living taxa that we could sample,” she added, “it would be interesting to see how they may have changed, even if they didn’t go extinct.”

“There’s interesting work that’s been done,” she said, referring to research of one of her colleagues, “[regarding the origins of] fossil deposits that indicates mastodons may have retreated to a particular part of the United States just before the Terminal Pleistocene.”

The Pleistocene is a period of time on earth that dates from about 2 million years ago through about 11-10, 000 years ago. The ‘Terminal Pleistocene’ refers to an extinction event within this period.

“Prior to the Terminal Pleistocene, they were found all over the United States. At the Terminal Pleistocene, they’re only found in a little tiny patch of the United States. Something affected their distribution. And I call it ‘retreat’ because it’s a much smaller distribution than they had before.

“By analyzing isotopes in bones and teeth, we would potentially be able to build off of these fossil distributions to paint a more interesting ecological picture of the Terminal Pleistocene.”

Painting more interesting ecological pictures is a strong focus of Dr. Crowley’s work. A scientist who has travelled extensively throughout the world, her research has taken her to the Canary Islands, the Dominican Republic, Trinidad and Madagascar. Reading her blog and her website, one recognizes a distinct fondness for the aforementioned African country.

Embed from Getty Images

When asked if Madagascar was where her heart was, she responded, “In many ways, yes. Part of that is that I’ve devoted a lot of time and energy into learning a lot about it. So, now I’m invested.”

“There are certainly conservation issues in our own country,” she continued, “but there are other places–and Madagascar is one of them–where there’s a real need to try to make some changes happen now for future conservation and biodiversity management.”

“Up until recently, the recent past of Madagascar was rather understudied. It turns out that there are a lot of interesting questions that are still unanswered.”

Her website, Agoraphotia.com, describes her specific interests:

I investigate ecological interactions among living and recently extinct animals using stable isotope biogeochemistry. My interests include niche partitioning, conservation biology, and paleoecology. I am particularly interested in the causes and consequences of recent extinctions, and the ecological repercussions of habitat fragmentation and degradation.

She has studied fossilized rodents, lemurs and orangutans; she has researched climate change; she has studied plants and soil.

She lists research projects in which she has been involved:

•Assessing the utility of stable oxygen isotopes in distinguishing dietary niches.

•Distinguishing isotopic niches of fossil rodents in the Dominican Republic.

•Establishing the stable isotope ecology of modern and Prehistoric Trinidad.

•Exploring ecological change following human settlement on the Canary Islands.

•Identifying responses of the animal community to climate change and human impacts in Madagascar.

•Quantifying spatial variability in bioavailable strontium and assessing changes in mobility patterns of extinct and extant North American megafauna.

Prior to the University of Cincinnati, she lectured at the University of Toronto and volunteered at the Royal Ontario Museum in the OWLS (Open the World of Learning to Students) program.

She describes herself as “a relatively new professor in Cincinnati”, one who actively works to try and include students into her research projects. In this, she feels she has been successful, as she has had a number of students involved in her postdoctoral and graduate research and currently has students working with her in the lab.

The study of proboscidean teeth that lead to the paper to be published in Boreas was, she said, “originally designed to be a student project.”

Given her vast and varied experience, one might wonder why the focus was extinct North American fauna.

Explaining that most of her students are either from Ohio or the surrounding region, she said, “It’s a little more relevant for them to think about animals that lived in their backyard than animals that lived on the other side of the planet.”

This, too, is why they used teeth from the Cincinnati Museum of Natural History, rather than the collections of other neighboring state museums.

Brooke in Madagascar2

[image of Dr. Crowley in Madagascar next to a sign that warns visitors that “Lake Ravelobe is forbidden” and that “Crocodiles attack”; courtesy of Dr. Crowley]

“Many of the reasons that I do what I do and that I am where I am is because of other people who have helped me along the way or inspired me. And really one of the biggest reasons that I wanted to go into academia in the first place was because I feel like I have been empowered in many ways to try to make a difference.

“And I feel like that’s something that I can share with others and then try to make a difference by empowering others and helping them find their way and be compassionate as well.

“So that’s sort of my goal.”

She chuckled. “I don’t know how much I have really met that goal, but I do try, and I’m still pretty new to being a professor. So, I’m finding my way. It’s a challenge, but it’s a good learning experience, and I find it to be pretty rewarding.”

Brooke on a promontory in Tenerife

[image of Dr. Crowley on a promontory in Tenerife, Canary Islands; courtesy of Dr. Crowley]

———————————–

A Mammuthus primigenius-sized THANK YOU to Dr. Brooke Crowley for her generous time, help and fascinating responses to my questions!  What a great honor to connect with her!

You can read the paper in Boreas, Stable isotopes reveal ecological differences amongst now-extinct proboscideans from the Cincinnati region, USA:  http://onlinelibrary.wiley.com/doi/10.1111/bor.12091/abstract

I had a very difficult time grasping the concept of isotopes. This is due to my struggle with chemistry in general and not a reflection of the gracious people below who took the time to try to help me understand it.  I extend sincere thank you’s to:

  • Dr. Brooke Crowley
  • my dad
  • my sister-in-law who studies science
  • Dr. Suzanne Pilaar Birch (@suzie_birch)
  • Ariel Zych (@Arieloquent) and Science Friday (@scifri)

If you are interested in understanding more, here is further reading:

  1. Dr. Brooke Crowley, Stable Isotope Ecology: http://crowleyteaching.wordpress.com/courses/stable-isotope-ecology/
  2. Stable Isotopes in Zooarchaeology: http://sizwg.wordpress.com/bibliography/
  3. New insight from old bones: stable isotope analysis of fossil mammals, by Mark Clementz: http://www.mammalogy.org/articles/new-insight-old-bones-stable-isotope-analysis-fossil-mammals
  4. Applications of Stable Isotope Analysis, K. Kris Hirst: http://archaeology.about.com/od/stableisotopes/a/si_intro.htm

Meet Lyuba – Mummified Baby Mammoth in London

“She’s beautiful.”

So exclaimed Professor Adrian Lister upon seeing Lyuba as the lid to her crate was first opened in London. Lyuba is a 42,000-year-old baby mammoth, and her state of preservation is breathtaking.

”It was an emotional experience to be face-to-face with a baby mammoth from the Ice Age,” Professor Lister said. “I’m so thrilled that our visitors will be able to experience that, too.”

NHM-DrListerLyubawelcome

[image of Professor Adrian Lister with Lyuba, courtesy of Natural History Museum, London]

Her discovery occurred in 2006, thanks to a family of Nenets reindeer herders in Siberia. Lyuba was initially found–her body partially exposed in the snow–by Yuri Khudi’s son. She was recovered in the spring of 2007, and she is named after Mr. Khudi’s wife.

NHM-YuriKhudiSon

[image of Yuri Khudi and son, courtesy of Natural History Museum, London]

If you are in London, you can actually see her on exhibit in Mammoths: Ice Age Giants currently at the Natural History Museum.

Mammoths: Ice Age Giants is a traveling exhibit from The Field Museum, Chicago. Since 2010, it has been seen throughout the United States (albeit under a slightly different title), but most museums have included a replica of the baby mammoth.

LyubainBoston

 

[image of Lyuba replica, taken by the author’s cellphone at the exhibit in Boston, 2012]

The replica is remarkable. But the opportunity to see Lyuba herself is extraordinary.

When asked how the Natural History Museum was able to obtain the actual mammoth, Professor Lister wrote, “The Museum worked closely with Lyuba’s home institution, the Shemanovsky Museum – Exhibition Complex in Siberia, Russia to get the opportunity to showcase Lyuba as the star of the show in Mammoths: Ice Age Giants. This involved complex contract negotiations and we are very grateful to the Shemanovsky Museum for the loan of such an important specimen.”

Hilary Hansen, one of the Field Museum’s Traveling Exhibition Managers, explained that only one of the US museums has been able to showcase Lyuba thus far.

Surprisingly, the reason is not related to cost.

“[T]he Russian government has a moratorium on loans to the US,” she wrote, “so only international venues get to host her.”

(You can read more about the origins of this moratorium here: http://www.nytimes.com/2011/02/03/arts/design/03museum.html)

And how does one ship and display such a rare and enormously valuable specimen?

It was explained that Lyuba has been thawed since discovery, but her body was essentially freeze-dried over the course of her 42,000 years of burial. She traveled to London in a purpose built wooden case which has padding/foam fitted specifically to her body inside so as to protect her during travel. Within the exhibition, she will be displayed in a climate-controlled and sealed case.

NHM-LyubaVisitors

[image of Lyuba and visitors, courtesy of Natural History Museum, London]

So much has been learned about mammoths since her discovery. Through CT scans, autopsies, and other tests, scientists have been able to ascertain more about her diet specifically and mammoth biology in general.

NHM-LyubaScientistsRussia

NHM-LyubaScientistsLab

[images of Lyuba and scientists, courtesy of Natural History Museum, London]

 

An exciting example is described in Professor Lister’s latest book, Mammoths and Mastodons of the Ice Age: the discovery of a pharyngeal pouch between the larynx and the back of her tongue. He discusses the relatively recent knowledge of this anatomical feature in today’s elephants. The pharyngeal pouch can be used for communication and to store water. Elephants in Namibia, he explains, have been seen reaching into their mouths with their trunks and spraying themselves with water they had drunk hours before. (page 80)

Pieces of material believed to be partially digested milk from Lyuba’s mother were found in her stomach (page 84), and her intestinal contents point to a practice used in today’s elephants as well: eating adult elephant feces as a way to introduce needed bacteria for digestion. (pages 84-85)

These are the kinds of exciting details one can explore in this exhibit. Using interactive displays, fossils, sculptures and other artwork, this exhibit not only introduces the visitor to some of the fascinating research being conducted today, but also summarizes some of what we’ve learned about proboscidea to date.

There is a video describing Lyuba’s discovery, and another explaining the remarkable details one can learn from mammoth tusks, both of which feature Dr. Daniel Fisher of the University of Michigan (one of the original scientists who studied Lyuba). There are videos behind possible mammoth behavior, as well as the types of ancient vegetation discovered in soil specimens.

Life-sized models of Pleistocene fauna, including a short-faced bear, a saber-toothed cat and an enormous Columbian mammoth, give added depth to what most would only see in their fossil remains.

Columbian mammoth replica

[image of Columbian mammoth model, courtesy of Natural History Museum, London]

Artwork can be found throughout the exhibit. In a striking display of the diversity of these animals, a sculpture of a dwarf mammoth stands beside a bas-relief of an elephant, a mastodon and a Columbian mammoth. Full-sized fleshed-out sculptures of proboscidean heads—species that lived prior to mammoths and mastodons—extend from the wall.

And fossils—numerous teeth, skulls, tusks and bones—from mammoths, mastodons and other Pleistocene animals can be seen throughout. A cast of the Hyde Park mastodon from New York gives visitors a chance to walk around a complete fossil and see it from every angle. The replica of a mammoth fossil in-situ lies below a time-lapse video of what a particular landscape might have looked like from the time of that mammoth to the present day.

NHM-Mastodon

[image of Hyde Park mastodon cast, courtesy of Natural History Museum, London]

The exhibit is geared toward all ages, with activities for children through adults, and having prior knowledge of mammoths or paleontology is not a prerequisite.

“A key element of the exhibition for the family-focused audience is the interactive activities,” wrote Professor Lister, “such as feeling the weight of the food a mammoth ate in one day, trunk moving and tusk jousting.”

Given its popularity and the success with which it introduces a wide variety of people to the subject, one might wonder how the exhibit took shape.

“The idea originated from staff at the Field Museum several years ago. It was one of several ideas that came about during a process of brainstorming ideas,” Hilary Hansen explained. “The other topics that came about were George Washington Carver, natural disasters, and biomimicry. We tested these topics, along with many others, with visitors, the general public, museum members, and other museums around the country but those were the ones that rose to the top. It helped that the frozen baby mammoth, Luyba, had recently been found in Russia.”

“The whole process took about 3 years, I’d say,” she continued. “And as a whole, probably involved 60+ people to identify and conserve the specimens, develop the content with curators, design the exhibitry and graphics, source and license ages, build interactives, create videos, and build the show.”

“We did a lot of visitor studies and market research before we created [it]. I can’t say that we’ve received any feedback that startled us. It’s been very well received. In fact, the Times gave it 5 stars. That was wonderful.”

The exhibit has been seen from places as far as Chicago to Anchorage, from Boston to San Diego, but recently, from Edinburgh to the relatively nearby London.

When asked if the two recent locations in the UK were a coincidence, Hilary wrote, “We booked these two venues about 3 years ago. We were deliberate in finding 2 consecutive venues in the UK so they could share shipping expenses, which can be significant for an exhibition of this size. These two museums have worked together in the past so it was a smooth transition from one venue to the next. We book our exhibitions about 2 or 3 years out, though there are some exceptions.”

The exhibit has not changed since its inception. But, she wrote, “[s]ome venues have added graphics or specimens for their presentation, if it pertained to their own programming and collections.”

As an example, she added, “The Denver Museum of Nature and Science added a whole section about their Snowmass excavation site. But that didn’t continue on with the tour.”

Which makes the Natural History Museum an exciting place for this exhibit to temporarily reside. Proboscidean experts, Dr. Victoria Herridge and the aforementioned Professor Adrian Lister, are employed there and gave talks about their research. They have, in fact, resurrected the work of Dorothea Bate—an inspiring fossil hunter of the early 1900’s who discovered dwarf mammoth fossils in Crete—and have shed new light on her work.

NHM-DrHerridgeLyuba

[image of Lyuba and Dr. Victoria Herridge, courtesy of Natural History Museum, London]

“Other researchers must have visited the collections to look at the fossils,” Dr. Herridge explained, referring to the fossils Bate brought back to the museum, “but to the best of our knowledge we are the first to have published a taxonomic study based on the fossils themselves (rather than simply referring to Bate’s own papers or Osborn’s Proboscidea). This probably reflects the resurgence of interest in island dwarfing as a research topic in recent years.”

Dwarf mammoths—smaller versions of larger species, as their name implies—have also been referred to as ‘pygmy’ mammoths.

Is there a difference?

Dr. Herridge wrote, “The terms are used synonymously for the most part. I prefer to use ‘dwarf’ for island dwarf hippos because it helps to differentiate them from the extant hippo species Choeropsis liberiensis which has the common name ‘pygmy hippo’ — this species is not the same as the island dwarf hippos, and did not evolve to be small because of an island environment, and using dwarf helps to avoid confusion on this subject. Similarly, there is a cryptozoological belief in the existence of a ‘pygmy elephant’ in the jungle of West Africa, and using ‘dwarf elephant’ for small island elephants helps to avoid confusion here too. And to be consistent, I then also use dwarf for the small island mammoths and deer as well.”

Information on the Museum’s website indicates more work needs to be done.  It was explained that “[c]urrently there are no dates whatsoever associated with the Cretan mammoth fossils, and only a small number of dates for fossils on Crete in general. With colleagues from U. Bristol, U. Oxford and UCLA, Dr. Herridge and Professor Lister are currently working on a project to date many of the sites that Dorothea Bate excavated on Crete, including the dwarf mammoth locality. They have relocated the sites, and then taken samples for uranium series and optically stimulated luminescence dating. No new excavations for fossils have been carried out as yet, but if the results prove interesting more may be done in the future.”

NHM-ColumbianMammothSkull

[image of Columbian mammoth skull and tusks, courtesy of Natural History Museum, London]

 

“The exhibition will allow visitors to enter the amazing world of some of the largest creatures to have ever walked the earth,” concluded Professor Lister. “[Mammoths: Ice Age Giants] will take visitors on a journey from the time when these titans roamed the land through to today’s research into the causes of mammoth extinction, using new scientific research from the Natural History Museum.”

———————–

Watch a video of the exhibit! Mammoths: Ice Age Giants – “It’s not just the bones!” | Natural History Museum

More information from Dr. Victoria Herridge about dwarf mammoths! Identification of the world’s smallest mini mammoth | Natural History Museum

And learn about the possible causes of mammoth extinction from Dr. Adrian Lister! The Last of the Mammoths | Natural History Museum

Visit the Natural History Museum in London before 7 September 2014 to see this fascinating exhibit! http://www.nhm.ac.uk/visit-us/whats-on/temporary-exhibitions/mammoths-ice-age-giants/

Watch Waking the Baby Mammoth from National Geographic (written by Adrienne Ciuffo) to learn more about Lyuba’s discovery: http://www.natgeotv.com/asia/waking-the-baby-mammoth/videos/waking-the-baby-mammoth

Order a copy of Mammoths and Mastodons of the Ice Age by Professor Adrian Lister for more fascinating details about proboscidea: http://www.fireflybooks.com/bookdetail&ean=9781770853157

Dr. Victoria Herridge will have a new book published in 2015, The World’s Smallest Mammoth: http://bloomsburywildlife.com/victoria-herridge/

Extreme insular dwarfism evolved in a mammoth: Paper written by Dr. Herridge and Professor Lister, their research of dwarf mammoths on Crete, initiated by Dorothea Bate in the early 1900’s

A Mammuthus meridionalis-sized THANK YOU to Dr. Victoria Herridge, Professor Lister, Hilary Hansen and Helen Smith for their time, their help and their generous responses to my questions! What a great honor and a true pleasure!!