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!

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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]

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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)

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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.”