Dr. Advait Jukar – Solving Mysteries in South Asian Fossil Communities

Dr. Advait Jukar–Deep Time – Peter Buck Fellow at the Smithsonian Institute–wants to really understand ancient ecosystems in South Asia, but doing so means beginning with some of the very basics. Challenges include not just a lack of available fossils from the region, but also the lack of detailed records from early paleontologists and a dearth of contemporary research.

He is, in a sense, an explorer.  (All paleontologists are.)  If we think of paleontology as a sculpture in progress, many scientists are working on the fine details.  Dr. Jukar, on the other hand, has the clay and the tools, but the sculpture itself hasn’t even begun to take form.

Consider what he has to work with: isolated proboscidean teeth and skulls, for example, collected by Hugh Falconer and his crew in the early 1800s.  They didn’t record where the bones were found, let alone where each fossil was in relation to the other.  Those who later described these fossils made dubious claims regarding the species.  And few people to this day have revisited this data or expanded upon it. 

 

Image of Dr. Advait Jukar at work with an Elephas hysudricus molar; courtesy of Dr. Jukar

 

Compare this to Maiasaura fossils in the Northwest US.  So many fossils of this species have been excavated that Dr. Holly Woodward Ballard has created the Maiasaura Life History Project.  Its goal is to uncover more details about this particular species than any other currently known extinct creature.  She has a wealth of data at her disposal. Unlike Dr. Jukar, the fossils she can study have been found fairly well articulated, very well documented, and in remarkable abundance.  There are adults, sub-adults, juveniles and embryos.  She and her colleagues are able to add to existing scientific literature using the latest technology.  It’s an exciting project with absolutely fascinating possibilities.

 

FIGURE 6. Survivorship curve for Maiasaura. Sample size of 50 tibiae was standardized to an initial cohort of 1000 individuals (assumes 0% neonate mortality). Survivorship is based on the number of individuals surviving to reach age x (the end of the growth hiatus marked by LAG x). Age at death for individuals over 1 year old was determined by the number of LAGs plus growth marks within the EFS, when present. Error bars represent 95% confidence interval. Mean annual mortality rates (μ^) given for age ranges 0–1 years, 2–8 years, and 9–15 years. Vertical gray bars visually separate the three mortality rate age ranges; courtesy Dr. Woodward Ballard for this post

 

 

 

But so, too, is Dr. Jukar’s intended research.   Focusing on the tail end of the Neogene, about 4 million years ago, through the Quaternary, he wants to understand herbivorous mammals—their community, their ecology, their biogeography.  It’s just a question of building the necessary foundation first.

“I started to compile all of these species lists,” he explained by phone, “and saw that there were lots of species of proboscideans in South Asia during that period of time.  We have gomphotheres; we have stegodons; we have elephants.”

One way to understand an animal’s impact on its environment is to assess its body mass.  How big (or small) were these animals?  And therefore, how much did they need to eat?  A larger animal would presumably need to eat a larger amount of vegetation.  Similarly, a larger animal might reproduce less frequently than smaller animals.  Body mass reveals clues about how an animal fits into the ecosystem.

However, he continued, “I hit a wall because there was no way for me to estimate how big these elephants were.  The problem was they were largely known either from skulls or teeth, and the traditional methods to estimate the weight of an extinct elephant were using shoulder height or the length and circumference of the long bones. So if I have a skull but I don’t have long bones, I’m sort of in a bind, because now I can’t estimate how much this animal weighed when it was alive.”

He looked to methods that others have used in the past. One method used by his colleagues at Howard University seemed to be a promising fit.  They used the occipital condyle breadth of seacows—a proboscidean relative–as an indicator for body mass.  Dr. Jukar’s PhD advisor, Mark Uhen, mentioned that this method had also been used on yet another large mammal: the whale. 

The occipital condyle is a bone found at the base of the back of the skull, connecting the skull to the spinal column.  It’s a relatively small bone.  Why would this have an impact on determining body mass?

“If occipital condyle breadth is correlated with the size of the animal,” Dr. Jukar said, “and if the occipital condyle is the point where the skull attaches to the rest of the skeleton, then maybe the size of the skull scales with the size of the overall body. And if that’s true, then maybe the occipital condyle breadth will scale with the size of the limb bones as well.”

 

Image of the back of a mastodon (nicknamed ‘Max’) skull at the Western Science Center in California displaying the occipital condyle bone resting on the metal stand; photo taken by Jeanne Timmons

 

In other words, if a paleontologist has but one skull of an extinct proboscidean and no other related fossils, can that person measure the breadth of the occipital condyle as a way to determine the size and weight of that animal?

To test this theory on proboscideans, he researched available scientific literature and visited a number of museum collections.  Ultimately, he and his two co-authors, S. Kathleen Lyons and Mark Uhen, compared the occipital condyle breadth to the length and circumference of leg bones within extant elephants and extinct relatives.  Two elephant species were studied, as were six gomphotheres, three mastodons and one stegodon.  

Image of a fossil Moeritherium at the Yale Peabody Museum; photo taken by Jeanne Timmons

 

While careful to note that this method has its limitations, the results were promising.  The equations are different for each proboscidean family (gomphothere body structure and size is not the same as that of a mastodon) and they do not work for some of the smaller proboscidean species, such as Moeritherium.  In layperson’s terms, this research works for taller, lumbering proboscideans, not those with much shorter limbs and a perhaps waddling gait. Their paper and its results were published in the Zoological Journal of the Linnean Society: A cranial correlate of body mass in proboscideans.

This, though, is just the tip of the iceberg in terms of Dr. Jukar’s research.  An enormous collection of fossils from India resides in the Natural History Museum of London.  Found in an area referred to as the Siwalik Hills (or the “Siwaliks”) at the base of the Himalayas, Scottish paleontologist Hugh Falconer and his team collected them in the 1800s.  Among them are several stegodon teeth and skulls. 

Image of Dr. Advait Jukar measuring a Stegodon ganesa fossil in the Natural History Museum of London collection; courtesy of Dr. Jukar

 

The two species of stegodon excavated from the Siwaliks are, to this date, known as Stegodon insignis and Stegodon ganesa.  The species have very similar teeth, but their skulls seem to differ greatly.  The skull of S. insignis, according to Dr. Jukar, is “almost triangular in shape with relatively small tusks,” which Falconer chalked up to sexual dimorphism.

“Which I just thought was the weirdest thing to ever say about stegodons because the skulls are clearly different. They’re clearly not sexually dimorphic.”

Moreover, there seems to be confusion regarding which fossils Falconer assigned to which stegodon species that continues to this day.  

“So what was going on in his mind? I have no idea.  It’s a problem! Because since then, people have said that both of these must be the same species without really truly investigating them. 

“Any Stegodon tooth that they’re finding in the Siwaliks, they’re calling Stegodon insignis or Stegodon ganesa or a hyphenated version of the two: Stegodon insignis-ganesa, which is taxonomic heresy.” 

And here Dr. Jukar was emphatic: “You CANNOT do that with the taxonomic code.”

“And that was Osborn’s fault.”

He was referring to Henry Fairfield Osborn, former professor then curator of the American Museum of Natural History in the late 1800s.

“Osborn [is known to have asserted], ‘I agree with what Falconer said, so I’m going to hyphenate these two words.’  Which created such a mess.  So we have no idea what’s going on there. 

“There’s a lot of work to be done with elephant taxonomy, biogeography and systematics and comparisons between China, the Levant, East Africa and India.”

 

Image of the Levant (Public Domain)

 

Dr. Jukar and other colleagues have also recently published papers on the earliest known fossil of Hexaprotodon, an extinct hippo, from South Asia, and the first record of a Hippaprionine horse (Plesiohipparion huangheense) from the Indian Pliocene.

He is currently working with Dr. Adrian Lister of the Natural History Museum in London to further understand the various proboscidean fossils in the Siwalik collection.

This is important work, but Dr. Jukar pondered its reception to the wider world.

“For a long time paleontologists have been criticized as being mere stamp collectors because we find things and then we name them and then we try to figure out in what larger group they belong to.  But that is the basis of our data.

“Only when I have a comprehensive sense of what the species are, when they lived and where they lived can I start doing these more complicated community-level analyses.

“But because the basic science of naming a fossil might not be very exciting, [as it doesn’t directly impact] human life very much, it doesn’t get a lot of attention. 

“I am definitely interested in the big picture questions of dispersal from Africa into South Asia, about the ecology of these groups, about how communities have changed through time, but I can’t really do a rigorous analysis until I figure out who the [basic] players are in this place.”

Image of Dr. Advait Jukar with a Mammuthus columbi (Columbian mammoth) skull; courtesy of Dr. Jukar

 

References:

  1. Colbert E. (1996). Henry Fairfield Osborn and the Proboscidea. In:  Shoshani J, Tassy P. The Proboscidea : evolution and palaeoecology of elephants and their relatives, Oxford: Oxford University Press, xxii – xxv
  2. Dr. Advait Jukar’s website: https://advaitjukar.weebly.com
  3. Jukar, Advait M., Lyons, S. Kathleen, Uhen, Mark D. (2018.  A cranial correlate of body mass in proboscideansZoological Journal of the Linnean Society, Volume 184, Issue 3, 20 October 2018, Pages 919–931, https://doi.org/10.1093/zoolinnean/zlx108
  4. Jukar, Advait M., Patnaik, Rajeev, Chauhan, Parth R., Li, Hong-Chun, Lin, Jih-Pai (2019). The youngest occurrence of Hexaprotodon Falconer and Cautley, 1836 (Hippopotamidae, Mammalia) from South Asia with a discussion on its extinction, Quaternary International, January 2019, https://doi.org/10.1016/j.quaint.2019.01.005
  5. Jukar, Advait Mahesh, Sun, Boyang, Bernor, Raymond Louis, (2018). The first occurrence of Plesiohipparion huangheense (Qiu, Huang & Guo, 1987) (Equidae, Hipparionini) from the late Pliocene of India,  Bollettino della Società Paleontologica Italiana; 57(2):125-132 · August 2018
  6. Saegusa H. (1996). Stegodontidae: Evolutionary Relationships. In:  Shoshani J, Tassy P. The Proboscidea : evolution and palaeoecology of elephants and their relatives, Oxford: Oxford University Press, xxii – xxv

 

It was a GREAT pleasure and honor speaking with Dr. Advait Jukar.  Many, many thanks for your time, Advait, your help, your fascinating insight and your gorgeous images!! I cannot wait to read your future scientific papers!

 

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The Elephant Listening Project – Communication and Conservation

“One thing that surprised me was how much noise they made when they rubbed their bodies on tree-trunks (which they do a lot) and flapped their ears.”

Liz Rowland, data analyst for the Elephant Listening Project, recalled one of her few field trips in Gabon.  In this instance, she and Peter Wrege—director of the ELP (Elephant Listening Project)—were observing elephants at night with the help of infrared floodlights and night-vision binoculars.

“It was also obvious how great their sense of smell was. If the wind was going from us to them, they’d often all put up their trunks in the air (called periscoping) to smell us. Quite amusing.”

Sierra Exif JPEG

[Image of elephants in Dzanga Bai (Central African Republic) drinking at the mineral pits taken by Andrea Turkelo, courtesy of the Elephant Listening Project]

Gabon is one of the African countries in which the ELP works and one of the limited places left in the world home to wild herds of elephants.

“The only staff employed in ELP are me and Peter,” Liz continued, “and we’re here in Ithaca nearly all the time, so our fieldwork is quite limited. Mostly, it involves just Peter Wrege going out to an area and trekking through the forest to put up recording units. He’s been going out to one area or another a few times per year.”

Andrea Turkalo, a scientist who has studied elephants for over 20 years, is another member of the team, even if she is not technically employed by the ELP.

What has become standard practice—regularly recording and analyzing elephant sounds–was an original idea in the 1980’s.  The ELP’s founder, Katy Payne, had spent fifteen years listening to whales with her then-husband, Roger Payne. Her curiosity as an acoustics biologist veered toward elephants in 1984. So she visited the Washington Park Zoo in Portland, Oregon, to listen to the Asian elephants residing there.

In her book Silent Thunder, Katy Payne describes her introduction to those zoo elephants, to the social hierarchy evident in that brief visit, and, eventually, of six trunks extending through the bars, “gently surrounding [her] with whiffing” [page 17], as they explored her scent.  It was that visit, in which she felt rather than heard a throbbing in the air, that prompted her to question whether elephants made sounds that humans might not be able to detect.

She acknowledges that she was not necessarily the first to make this observation.  She points to M. Krishan, who made such a suggestion in 1972, and to Judith Berg of the San Diego Zoo. (page 44)  Elephant scientists such as Cynthia Moss and Joyce Poole in Kenya as well as Iain Douglas-Hamilton in Tanzania had wondered how elephants could appear to communicate without any apparent sound over long distances. (page 43)

Katy Payne was, it seems, the first to act upon it and undertake ongoing studies to research it further.  Her tape recordings of elephants at the zoo revealed communication through infrasound.

Her research in the 80’s and 90’s took her to a number of African countries: Amboseli Park in Kenya, Etosha National Park in Namibia, and the Sengwa Wildlife Research Area in Zimbabwe.

Her teams’ recordings were brought back to Cornell University, situated in the rolling hills of Ithaca, NY.  And there, they were further analyzed. The Elephant Listening Project found its home in–of all places–the Ornithology program within that institution.

“[I]ndeed, people are usually surprised that we’re based at the Lab of Ornithology!” Liz Rowland explained. “The reason is to do with acoustics. I think there was already a sound library here for bird song when Katy established ELP. There was also another link I think. Chris Clark was already here at the Lab as head (and founder) of the Bioacoustics Research Program, working on whale sounds. Chris had previously worked as an assistant to Katy when she was working on whales. So I think that helped get Katy started here.”

Over the years, the areas in which the ELP works have changed slightly.

“Peter works with people based in Africa, often associated with the Wildlife Conservation Society, who suggest or request sites,” Liz wrote.

ELP - Langoue_grp

[Image taken by Peter Wrege, courtesy of the Elephant Listening Project]

“There’s usually a specific need for information about the elephant and/or poaching activity. For example, Parks’ or Wildlife Conservation Society staff might be especially concerned about poaching in an area, or local people might be thinking of setting up an ecotourism project and would like to know when/where best to set up a platform [for wildlife viewing.]”

“[It’s] really only Peter that goes out to the field, although I did go with him once when we did a project that did need field observations. This was to confirm earlier studies by ELP where we found that the number of elephant calls recorded was a good indicator of the number of elephants observed at a forest clearing. So, we had to both make acoustic recordings and visual observations at a clearing.”

Communication between humans over such geographic distance offers its own obstacles.

“Unless he’s in one of the towns en route to the field, [Peter] doesn’t have any contact [with other ELP sites] except by expensive satellite phone.  Andrea Turkalo is usually based in Dzanga National Park, [Namibia], where she has limited email access and a satellite phone.”

When asked about the greatest challenge to the ELP, however, Liz responded, “Funding! We’re always on the edge of having no money at all! There are only 2 of us and although we both work full time, we don’t have funding to cover that in salary. We really need to be able to pay skilled computer programmers to help us progress, and although there are several people here in the Bioacoustics Research Program (of which we are a part), ELP has to be able to pay for their time if we want their help. Funding from grants has been increasingly difficult to obtain.”

The feeling that she’s “doing something to help conserve an extremely endangered species” is what Liz notes as the most rewarding aspect of her job at ELP.

“My interests have always been with animal behavior and conservation.”  She noted that living in South Africa for several years prompted her love of Africa in general. “Communication and social behavior of mammals, especially African mammals, has always held a special lure for me.”

“I used to work in a different department at Cornell (Natural Resources),” she continued, “which was quite interesting work, but was geared towards figuring out how to ‘manage’ wildlife (finding effective repellents, etc.), which was the wrong angle for me!”

ELP - Unequal V, VI 7

[Image of elephants in Dzanga Bai (Central African Republic) drinking at the mineral pits taken by Andrea Turkelo, courtesy of the Elephant Listening Project]

“Katy Payne used to give talks on campus every now and then about her work with the elephants so naturally I went along to them and was hooked! I kept asking if she had positions free but of course ELP had no spare funding. Eventually my contract with Natural Resources expired and Katy took me on as a volunteer. Then ELP got a little bit of money so they actually employed me, and so it’s been (on and off!) since then. Although I rarely get to actually see elephants, or even video of them, my motivation is that I’m helping to provide information that is needed to conserve them.”

Learning about elephants—let alone for a piece like this; one can only imagine what it is like in the field—is fraught with emotional highs and lows.

There are the beautiful anecdotes that demonstrate how highly intelligent and social these animals are.  One recognizes traits within elephant families that human families share: the adult tenderness with the youth in the group; baby elephants playing with one another; mischief created by the youth that is tolerated (or not!) by the adults; and the seemingly obvious grief for and memory of an elephant that has died, as the other elephants will touch and smell the bones of that elephant for years afterwards.

In one particularly amusing moment in Silent Thunder, Katy Payne describes how several juvenile male elephants—enormous creatures with an enormous combined weight—are stopped by the sight of a butterfly and then flee. (page 73)

One recognizes personalities within elephants.  One can see—from observers such as those at the ELP, who record interactions and describe them for those of us unable to witness them—how connected the elephants within each family or bond group truly are.

But then one cannot ignore the overwhelming information about elephant destruction: their numbers are dwindling at an alarming rate.

Most of their deaths are directly attributed to the ivory trade, an illegal market that kills thousands of these animals each year.  The reasons behind it and the people involved—from those with great economic need to those who are organized, well-funded and feeding an international demand—make this human/animal conflict messy, complicated and constant.

These numbers were painful almost two decades ago when Katy Payne wrote about them in Silent Thunder.  The numbers have only increased since then.

“[F]orest elephants are being killed at the rate of about 10,000 per year,” wrote Liz Rowland. “There may be only 100,000 forest elephants left.”

National Geographic included devastating statistics of elephant deaths throughout the world in  Bryan Christy’s 2012 article about the ivory trade. Within Central Africa, 90% percent of elephant deaths were attributed to ivory poaching; within Eastern Africa, those same figures were at 59%; in Western Africa, 84%; and in Southern Africa, 51%.  In that same article, it was estimated that African elephants alone numbered at 1.3 million in 1979.  In 2007, their numbers had fallen to a mere 472,000 – 690,000. (You can see that graphic and those figures here.) Given the annual death rate to the ivory market, today’s numbers can only be smaller.

Liz Rowland emphasizes this when she wrote, “The current threat to elephants is the ivory trade – mainly from the Chinese market. Everyone should do all they can to educate people about this whenever they have the opportunity (especially to those people who might consider buying ivory!)”

Also important, she noted, “Andrea and Peter are in the process of analyzing the data from [Andrea’s] 22-year long observational study at Dzanga National Park, and it shows that the reproductive rate is much slower than that of their savannah cousins, making them even more vulnerable to extinction.”

The length of time these researchers and their colleagues have spent in the field observing elephants is important. They have compiled a wealth of data that only continues to grow.

Even initially, Katy Payne mentions the creation of an elephant dictionary based upon their research.  Peter Wrege, in a relatively recent 60 Minute video, explains that the dictionary is still in its infancy.  It is one thing to learn another human language; the complexity of learning and accurately interpreting the language of another species altogether seems staggering.  It would be a remarkable achievement.

The members of ELP are not yet able to identify specific elephants by sound.

Wrote Liz, “At the moment, we’re too concerned with just getting the basic information about where elephants are, patterns of activity, etc., because this is essential for conservation planning, and we’re too short-staffed to do anything but the essentials.

“Andrea’s work is a separate project in a sense. There is one elephant there that has a unique call, but other than him, even Andrea isn’t able to ID the elephants by their calls.

“However, we think it’s very likely that the elephants recognize each other from their calls, and there has been some research on the Savannah elephant that shows that they are able to distinguish familiar from non-familiar individuals. The rumbles are very varied, so it makes sense that they can recognize calls. It would take a lot of work (time synchronized multi-channel audio recordings so that we could figure out where the elephant was when it called, with time synchronized video recordings) to figure this out.”

ELP - Thomas_ele

[A forest elephant named Thomas, taken by Peter Wrege, courtesy of the Elephant Listening Project]

As Katy Payne mused in Silent Thunder, “The more closely you watch elephants, the more complexity you see in their communities.” (page 63)

————————–

An absolutely enormous thank you to Liz Rowland of the Elephant Listening Project, who took precious time to respond to my questions and did so very generously!  An equally large thank you to everyone at the ELP, including Andrea Turkelo, and everyone within various African countries that work to preserve these animals.  And finally, a big thank you to my mom, who introduced me to Katy Payne and the Elephant Listening Project by giving me the book Silent Thunder.

Books (and magazine article) referenced:

  1. Silent Thunder: In the Presence of Elephants, Katy Payne, 1998, Simon & Schuster
  2. Ivory, Horn and Blood: Behind the Elephant and Rhinoceros Poaching Crisis, Ronald Orenstein, 2013, Firefly Books
  3. The Elephant’s Secret Sense: The Hidden Life of the Wild Herds of Africa, Caitlin O’Connell, 2007, Free Press
  4. Ivory Worship, Bryan Christy, National Geographic, October, 2012

You can help!  Adopt-an-elephant: http://www.birds.cornell.edu/brp/elephant/adoption/adoption.html

The Elephant Listening Project: http://www.birds.cornell.edu/brp/elephant/index.html

More info about Andrea Turkelo from NPR: http://www.npr.org/2014/05/08/309089369/civil-war-invades-an-elephant-sanctuary-one-researchers-escape

12.9.2014: Important updates on the ivory trade: two articles related to the massive number of elephant deaths for the ivory trade.  These two point to China as the major market behind this, adding that selling mammoth tusks is legal in that country.

(translate.google.com – if you need)

http://www.slateafrique.com/539707/ivoire-les-elephants-dafrique-menaces-dextinction-en-une-generation

http://www.tdg.ch/savoirs/environnement/chine-detient-cle-avenir-elephants/story/10373546:

“Le massacre des éléphants d’Afrique et le commerce de leur ivoire en Chine sont «hors de contrôle» et pourraient provoquer leur extinction d’ici une génération.”

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]

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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

Boston Archeology Fair – Spotlight: Matthew Lawrence

One of the presentations on October 19th at the AIA-MOS Archaeology Fair was “Ask Dr. Dig“, a panel discussion with four archeologists who work in four different milieus: one who works largely with road and bridge construction sites at the NH Department of Transportation, one who works as a city archeologist in Boston, one who works in Egypt, and the other who works in and around the ocean.

Highlighted on this post is Matthew Lawrence, a maritime archeologist who works at the Stellwagen Bank National Marine Sanctuary off of Cape Cod.

This was a fascinating discussion.

Because two of the four work at development sites, there was talk of “cultural resource management.” In other words, archeologists are often required to investigate a site before development can begin.  It is their job to make sure any archeological artifacts are removed appropriately.

Of particular note to me was something that Matthew Lawrence himself said in response to this part of the conversation: “It is only when things are being disturbed that archeology is undertaken.”

Ask Dr. Dig

(Information on screen highlighting the panel members at the Boston Museum of Science; picture thanks to Sheila Charles.)

Dr. Dig Panel

(Picture of panel members. From left to right: John Nolan, Joseph Bagley, Sheila Charles, and Matthew Lawrence; picture thanks to Sheila Charles.)

Matthew generously responded to my follow-up questions below:

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1. Have you always wanted to be a maritime archeologist?

Growing up I participated in an archaeology club at my local museum and once I learned to scuba dive, I knew exactly what I wanted to do for a career.

2. What kind of training does one need to be able to do archeology underwater?

In addition to learning about the theories and methods of archaeology, its usually necessary to become a proficient scuba diver. Alternatively, experience with advanced marine technology, such as remotely operated vehicles, can allow you to conduct archaeological research without getting your feet wet.  For those who would like to try out underwater archaeology, but not pursue it as a career, there are a number of avocational training programs available to teach the basics.

3. How do you preserve things that are found underwater once you bring them up?  Do you work in conjunction with other people and other fields to do so?

Artifacts recovered from the oceans require a lengthy and expensive conservation process that involves the removal of dissolved salts and the stabilization of the artifact’s structure.  Artifacts recovered from a freshwater environment may only need structural stabilization.  Specialists in the field of conservation are a vital component of any underwater archaeological research project.  These individuals typically have a greater understanding of chemistry than most archaeologists.  As in all archaeological research, much of the information learned about a site is found out in the lab.

4. During the discussion, you mentioned that the archeological artifacts you’d most want to find would be Paleoamerican artifacts.  What kinds of artifacts would these include?  And how would one find them (by digging underwater? is there any underground technology that might help?)

Evidence of paleoamerican habitation of the Stellwagen Bank National Marine Sanctuary could be found in the form of fire rings or stone tools.  It possible that organic materials also might be present in a buried context.  To locate these materials, archaeologists would use optical survey systems, sub-bottom profilers, and coring.

5. In your work at the Stellwagen Bank National Marine Sanctuary, do you often see whales?  Do you have any fun anecdotes about marine life you encounter?

I frequently see whales and other marine life on the surface, while conducting archaeological survey work.  When investigating shipwrecks on the seafloor, I usually find them teeming with a variety of fishes and invertebrates.  While diving on a shipwreck a few years ago, a large gray shaped passed close by me in my peripheral vision.  My first thought was BIG SHARK!!!!, but it turned out to be a large mola mola, a large, flattened, unusually shaped fish that I had never encountered near the seafloor.

Mola Mola Matthew Lawrence SBNMS

(photo of mola mola courtesy of Matthew Lawrence)

6. What do you like most about being an archeologist?

Archaeology is fun! The thrill of discovery when I find a new site or new information is followed closely by the enjoyment I get interpreting that information for an interested audience at a presentation.

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For more information about Stellwagen Bank National Marine Sanctuary: http://stellwagen.noaa.gov/

Many, many thanks to Matthew Lawrence for his fascinating answers and lightning quick response to my emails!