A number of curious readers have asked the obvious question: what does the “random journal entry” shown in my previous post read?
There are actually four entries on the two pages depicted, including 8-9 April 1923 and 5-6 April 1924. The entries for 8-9 April 1923 are the longest and most interesting. The entry for 8 April reads: “A very bad gale last night and today till evening and quite cold[.] went out on tide flat to get a Nesodon skull and lower jaws but tide did not go out far enough to uncover it[.] wind was so strong could not walk against it[.] in Afternoon wrapped specimens.” The next entry reads: “Very rainy until noon and cloudy till about 3 P.M. Prospected tide flat and did some wrapping specimens.”
This is no tall tale. Abbott was then encamped near the Rio Coyle, on the southeastern coast of Patagonia, and working in the mid-Miocene Santa Cruz beds. Anyone who has worked in this windy place will recognize the difficulties Abbott regales! Elmer S. Riggs, leader of the expedition, describes this weather vividly in an entry in his own journal with no date. He writes: “So strong…was wind pressure that men could not stand against it on the beach. Repeatedly we were dashed against rocks, caps and glasses blown away. Rocks were loosened from the cliffs and endangered our heads in the fall.”
Nesodon, now extinct, was a large-bodied notoungulate mammal endemic to South America. It was one of the more common Santa Cruz animals.
This post-Thanksgiving week, as you try to erase the memory of Uncle Henry indulging in his third slice of pumpkin pie, you may be delighted at the prospect of a distraction. In that case, try this one on for size. If your holiday meal included the traditional turkey, than you’ve just fed your family on the roasted carcass of a small dinosaur. Yes, that’s what I said, a small dinosaur. Feel better? Yeah… I didn’t think so.
Turkeys, like all birds, are members of a fascinating group of dinosaurs called theropods. Paleontologists love theropods, in part, because they were the Harry Houdini of the Cretaceous Period, managing a great escape when all other dinosaurs bit the big one 65 million years ago. This small factoid means that rather than always having to marvel at extinct animals, paleontologists can also study a small group of living dinosaurs in the flesh (how cool is that?!). And while living birds are cool, theropod dinosaurs on the whole were even cooler back in their heyday. Think: if birds are Maxwell Smart, than Cretaceous theropods are James Bond. This is because Cretaceous theropods also included animals like T. rex and Velociraptor, meaning that birds could have hosted some wicked and weird relatives at their holiday meals. (Can you imagine if cousin Utahraptor dropped by for Christmas dinner?)
Thankfully, a lot of Cretaceous theropods were more into veggies than flesh, including some very odd-looking and unusually large critters whose evolutionary history is just beginning to unfold. And while the benefit to your waistline that comes from choosing more vegetables over meat this holiday is clear, the same cannot necessarily be said for these veggie-loving theropod dinosaurs.
Scientists have long considered larger body size to be advantageous to vegetarian animals. Larger guts can fit larger digestive tracts allowing animals to get more energy from food with a lot of fiber and few calories. For that reason, scientists tend to think that bigger is better when it comes to plant eating animals. Interestingly enough, as you get closest to birds on the theropod family tree, the biggest species are also the ones we think ate plants not prey. Could this mean that feathered theropods fit the same pattern? A colleague of mine and I were dying to find out.
We began by estimating body mass for 47 species of feathered theropods representing three major groups that abandoned a strictly meat-eating diet–ornithomimosaurs (“bird-mimics”), oviraptorosaurs (“egg-thieves”), and the bizarre therizinosaurs (“scythe-lizards”). Our results showed that all three groups had members of gigantic proportions (up to 100 times more massive than an average person). The largest oviraptorosaur weighed over 7,000 pounds, and the biggest ornithomimosaurs and therizinosaurs topped out at over 13,000 pounds! rivaling the size of the great T-rex.
Nonetheless, just because some feathered dinosaurs got big, doesn’t mean that large size was an evolutionary advantage. To test whether these feathered dinosaurs were being driven to large body size by natural selection, we fitted a variety of evolutionary models to the data, looking to see which model best described the pattern. Turns out that plant eating theropods experimented with larger and smaller body sizes as they evolved and there was no clear drive to get big, no simple, overwhelming advantage to reach gigantic proportions. However, we did find one interesting pattern… different species from the same time and place tended to be about the same relative size.
Although we were a bit disappointed not to find a trend toward large body size, in a way this latter discovery was much more interesting. It suggests that changing environments during the evolution of these animals played a bigger role in body size evolution. Different climates, range sizes, resource abundance all exerted a stronger influence on the evolution of size than the simple relationship between eating plants and being big.
Of course, there are two other possibilities… first, these theropods might have been eating a high proportion of caloric plant material like fruits, nuts, and seeds instead of low fiber foods to begin with or, (and this one is always the elephant in the room for paleontologists), bias in the fossil record is messing with our data.
As in all good science, this research raised more questions for us than it answered. Back to the drawing board.
You can read more about this research in the November 28th online edition of the journal Proceedings of the Royal Society B. Thanks to my colleague Peter Makovicky of the Field Museum for his contribution to this blog post.
I needed some background information on the fieldworkers who accompanied the Captain Marshall Field Paleontological Expedition to Argentina and Bolivia (CMFPE), including George F. Sternberg, John B. Abbott and others. I asked one of my volunteers, Dick Webb, an avid genealogist, to search for documentation about these men on-line. He found a site that he claimed was chock full of information about Abbott. When I followed the link he sent me, I found many useful documents and pictures. At the bottom of the page, I found a name and contact information for the person who had posted the pictures – a distant relative of Abbott’s. I wrote to compliment her page. I mentioned my project involving her relative and the part he played on the CMFPE. She wrote back right away with some unexpected good news: she had a diary Abbott kept in Argentina. “Would I like it?” she asked!
A few days later a package arrived at the museum. Inside I found the original journal in perfect condition. I have been so busy with other things that I’ve hardly had any time to read it over. Every now and then, though, I take it out and read a few pages.
From what little I know I can tell readers this: the Abbott journal is now one of the best sources I have on the CMFPE. It’s a first-person, daily account of expedition activities. Many entries are rich with details about the weather, their itinerary, the fossils they discovered, etc.
I look forward to the opportunity to transcribe this journal and incorporate its contents into my book.
Lisa Schultz is bursting at the seams with excitement when we walk into Siemens Training and Development Center in Cary with our box of fossils. Since early morning, she’s been in this room testing the CT-scanner’s capabilities with a material that is quite a bit different than your average human body—a rock. Lisa’s “patient” is not just any rock, but a rather pretty hand-sized specimen with veins of crystalline quartz that her daughter found outside a couple of days before our visit. “Try this out mom,” she told her as she handed it over.
I met Lisa and the other incredible folks at Seimens this past March, when I came to “Take Your Kids to Work Day” to talk about new research on dinosaur fossils (my day job). After my presentation, Lisa pulled me aside and told me about a new dual energy scanner that the Center had, with a…
But if there’s one natural law even a croc can’t break, it’s eat or be eaten….
Two months ago I got the itch to go exploring (a chronic disease-process for paleontologists). Lucky for me, my colleague and long time curator of paleontology Vince Schneider had a fix. He was planning a day trip to hunt for the remains of ancient animals that lived and died in the lakes of North Carolina during the Triassic Period, some of which looked a heck of a lot like modern crocodiles.
After assembling a team of paleontologists and volunteers, we hit the…
When I cracked open the fresh binding on my senior yearbook an eon ago, I came face to face with the infamous superlatives list, bestowed (wittingly or unwittingly) upon various graduating members of our senior class. Nicest Eyes, Best Dressed, Most Likely to Open a Gas Station… the list was thoughtfully crafted.
After a few days in Africa observing living animals and taking data off the dead, it occurred to me that if there is one animal in Africa that deserves the award for Best Bite, it’s unequivocally the hyena.
The hyena gest this honor, not because it has the strongest bite—that record goes to another African native, the crocodile—but because it is an equal opportunity lender of mandibular destruction. Or to put it another way, a hyena doesn’t particularly care what it lends its jaws to. A hyena is no gourmand.
Time and time again, we found evidence of hyena feeding. It got to the point that when we approached a carcass the first thing that would run through our mind was: lets see what the hyenas left us this time… But the truth is, it was awe inspiring to see the damage hyenas are capable of inflicting with their teeth.
On every skeleton we found places where hyenas had gnawed off thin parts of bones entirely, such as the shoulder blade or hipbones.
They also appeared to be fond of chewing off the faces of elephant skulls.
We even found scat (droppings if you prefer) containing small bones that were swallowed whole by hyenas.
By far the wickedest evidence of hyena feeding was a turtle skeleton we stumbled across in the Kazakini area. The hyena had taken a young female leopard tortoise up in its jaws and bitten half of it clean off, right through the shell, no finesse required.
After all that, I thought I had a handle on the wreckage inflicted by the hyenas. Boy was I wrong. Laying in our tent one night I was startled awake by series of hideous sounds—the deep, desperate howls of a large antelope in its death throws overprinted by the frantic, murderous yips and cries of a whole pack of hyenas echoing like a twisted symphony across the grassland. Then suddenly like the fall of a black curtain, there was only dead silence. It was enough to make your blood run cold.
Next day we followed the footprints of the successful pack as they walked 50 feet from our campsite. For a moment the thought of following them to the kill site swept through my mind, but it was quickly followed by the memory of lunatic laughter.
I quickly came to realize I preferred studying the more distant aftermath of the hyena. Perhaps some things are best left to the cover of night.
I figured we’d be driving around on safari gazing through our binoculars at spectacular wildlife and documenting the incredible interplay of species struggling for survival in the African wetlands with our keen “super-scientist” powers of observation.
Then I remembered… we study dead things.
“What exactly are we going to be doing?” I asked, not really sure that I wanted to know the answer.
“Walking around looking for animal carcasses…” came the unfortunate reply.
“Of course,” I grumbled.
Now to be fair as a vertebrate paleontologist, I am used to studying skeletons… it’s just that, well, the animals have usually been dead for tens or hundreds of millions of years, so the “gross” factor isn’t really an issue. Even when I taught gross anatomy to med students, the cadavers were (thankfully) embalmed. To put it mildly, Botswana was a bit different.
Our first stop? An dumping ground with one dozen, I repeat, one dozen, fresh elephant carcasses baking in the hot African sun. (Thanks Bucky). Now you might ask, what might one dozen fresh elephant carcasses be doing in one spot? And that would be a fair question. I certainly wanted to know. Turns out that the government allots the local community here a certain number of permits for the hunting of elephants. In the Sankuyo Community this year that number was around two dozen. And this? This is where they compile the aftermath.
As a scientist, I generally take a matter of fact approach to data collection and I’m no neophyte when it comes to flesh and bone. So I was surprised to find myself suddenly surveying the morbid scene splayed out in front of me with a heavy heart. Having only seen elephants in the wild a few times in my life, they still held a certain majesty to me—an almost ethereal beauty—and it was hard to imagine a good reason for this loss of life. Later, in taking to the wildlife officer we learned that after the hunters flew home with their trophies (nearly all Americans and Europeans on the record books), the Community Trust distributes the elephant meat to feed the families within their care. (We’ll post more about this controversial and difficult topic later).
Sometimes the hardest part about being a scientist, is sticking to the data… but stick to the data we did.
After collecting our data on decomposition, predation and bite marks by hyenas, area of scatter, and so on, we paid reverence to the fallen elephants and headed off to find carcasses of animals that had died in the wild. Just as we were packing up to head out we witnessed a fleeting moment of beauty on one of the elephants, a Foxy Charaxes butterfly. We snapped a few photos for a colleague at NC State University who studies butterflies and went on our way.
As I climbed into the vehicle, my science-self was grateful for the reminder: in the natural world, death begets life.
In Africa, such reminders are not in short supply.