So Chapter 2! Mastodon Molars!

I love this chapter because it’s near and dear to my heart. The lab that I am a part of at UCLA is a paleobiology lab, meaning that many of us conduct research related to paleontology and biology, or in other words, how organisms are changing over time and why they are changing in the way that they are.

One of the things you may have picked up on in this chapter is just how much we can learn from studying teeth. They can give us information on diet, age, and even taxonomy/relatedness! The mastodon molars were so different from living elephant or extinct mammoth teeth that they perplexed and confused many a scientist at the time. I remember learning about just how much information there was in the teeth of these extinct animals when I was taking my first Vertebrate Paleontology course as undergraduate. All that information in something most of us barely think twice about! This was definitely one of the things that amazed and excited me the most about paleontology when I first started learning about it.

And finally, with this blurb I wanted to take the opportunity to shed some more light on someone very important who is only briefly mentioned in this chapter. Elizabeth Kolbert does a wonderful job of telling us about Georges Cuvier, the anatomist who correctly classified many of the fossils being found at the time, but one of the people who was finding many of these amazing fossils was a very interesting woman by the name of Mary Anning. At this point in time, when Georges Cuvier is studying and comparing the minute details of fossilized skeletal anatomy at the Paris Museum of Natural History, the people who went out searching for and collecting these fossils were predominantly white European men. Mary Anning was a notable exception. She is one of the first female “fossilists” or early paleontologists and she was quite accomplished, discovering a plethora of amazing and important fossils in her travels, including some amazing ichthyosaurs and plesiosaurs.

What did you think about the chapter? Have you ever thought about how we can tell species apart when all we have are pieces of fossilized bone? And did anyone else find it highly amusing that part of Lewis and Clark’s mission west was to find giant North American animals which in reality had been extinct for thousands of years?



In modernity we take for granted that the Earth and life on Earth changes, dramatically. The seven continents were united as one mighty Pangea and subsequently broke apart, periodically covered in ice or oceans or lava or forests. Enormous reptiles terrorized the land but do so no longer. Scores of animals lived and went extinct. We’re too familiar perhaps with these changes. A new species faces excition daily it seems, yet the concept that an entire type of animal could cease to exist is a relatively new one. In this chapter Kolbert provides a riveting history of the idea of exction. She attributes the birth of the idea to 19th century French naturalist and public scientist Jean-Leopold-Nicholas-Frederic Cuvier.

Kolbert set the scene for the chapter in the Ohio river valley in 1739, where another Frenchman, Charles le Moyne, second Baron de Langueuil, uncovered the first mastodon fossils while conquering new land with a small army of Europeans and Indians in tow. In a sulfurous marsh near Cincinnati, his men found something truly extraordinary. They discovered a thigh bone over a meter long, an “immense tusk”, and a clutch of enormous teeth, with “roots the length of a human hand”. The bones were sent to Paris. Naturalists at the time struggled to identify the beast or beasts, some attributing the tusks to some type of elephant and the teeth to an unknown hippopotamus. Later, President Jefferson, when he dispatched Lewis and Clark, hoped to find host of these bones roaming the forests of the Northwest in an effort to disqualify the sentiment of Europeans that American animals – and by extension the people- were feebler than those of the Old World. Jefferson disparaged the idea that animals could disappear from the Earth, writing that “no instance can be produced her having permitted any one race of her animals to become extinct.”

Enter Cuvier, who arrived at Paris’ Natural History Museum in 1795, a time when the bourgeois and aritoscrsy were taking to natural science in a serious way. During a public lecture in April, 1796 he presented his study of the Ohio incognitium, suggesting that the fossils belonged to a single elephant-like species. More shocking, however, he claimed the fossils belonged to especes perdues, lost species. Animals, Cuvier claimed, could indeed disappear from the Earth. Even more remarkable still, Cuvier suggested the “existence of a world previous to ours” and that a cataclysmic revolution in geology wiped these creatures out, leaving only their bones for us to cogitate upon. Cuvier became the preeminent authority on fossil anatomy and proponent of the idea that animals fade from history. Every new exotic fossil discovered or a quarry or cliff he attributed to now extinct species. In one public spectacle, he invited the Paris elite to watch as he chipped away at the rock around a mysterious mammal fossil uncovered in a local gypsum mine. At the time, the Old World possessed no marsupials, so, as the thinking went, there were never any such creatures. Chip away he did, however, to reveal the signature bones of a marsupial. The event increased Cuvier’s reputation  and he subsequently pushed his theory of lost species. 

Ironically, Cuvier laughed off the idea of evolution. At the time, scientists were beginning to understand that different strata of rock represented different eons. Rock further below was deposited earlier than rock above, and therefore the fossils uncovered from different rock were from different time zones. A contemporary history of Earth was emerging, one where life flourished for a bit before being wiped out by some unknown cataclysm. Secular and religious debate surrounded the development of both Earth’s evolution and the evolution of living systems. On the secular end, Cuvier’s senior colleague at the Natural History Museum, Jean-Baptiste Lamarck, was the first to suggest that species evolve from one another, albeit his theory was later found incorrect. As Lamarck suggested, the bird through repeated dives at the lake, developed webbed feet and becomes a duck. Cuvier failed to see the value in evolution and repeatedly buried Lamarck. On the religious side, a popular essay of Cuvier’s periodic cataclysms based on his geological and anatomical research was translated into English in such a way as to demonstrate support for Noah’s flood.

Later work disproved Cuvier’s hypothesis that dramatic events changed the face of the Earth. A story emerged that geology changed slowly, through tectonic movement and glaciation. His remarkable empirical work concerning fossils and extinction was accurate, however, and remains a testament to the immutability of science. Kolbert ends the chapter with a wry note that force that drove the mastodon to excition was likely humans, who hunted the woolly beasts to nothing as they occupied North America.


It’s always fascinating to hear the story of anyone who was the first of anything. I particularly enjoyed the story of Georges Cuvier because I’m always drawn to instances in science where individuals conclude a prevailing concept to be insufficient in explaining a natural phenomenon. It’s even more juicy when they go even further by probing deeper into the evidence and have the bravery to report their findings knowing the scrutiny they may face.

The discovery of Longueuil’s bones and the later attempts of classification are, to me, downright entertaining. I mean, you have to respect Jean-Etienne Guettard who was the first to look at the bones and said NOPE to even guessing the unknown animals’ provenance—which is just a fancy word that means place of origin. Next, in comes Daubenton who has the brilliant, but not so brilliant, idea that since the bones match nothing of known existence, it must be a smorgasbord of bones that come from multiple animals instead of one—seems reasonable. Then enters William Hunter, who was on the right track by disagreeing with Daubenton’s conclusion, but still missed the mark when he proposed it was a unique species of American Elephant.

In today’s society, extinction is a concept we are nearly too familiar with. Growing up, we’re taught what extinction is as we learn of dinosaurs of old, and the many endangered species we are striving to save today. It’s interesting to consider that the concept of extinction was so alien to those who were evaluating these bizarre bones back in the 1600-1700s, they were led to incorrect conclusions as to their origins. It was because Cuvier had the insight to see beyond what existed in his time, and place himself outside of the scientific biases that were guiding the conclusions of many others in his field, he was able to describe an entirely new phenomenon and share that with the world.

This strikes a chord with me because, as we have discussed on the show before, bias can be a powerfully confounding factor in how we formulate scientific questions and how we interpret what we observe. During Cuvier’s time the concept of extinction was ironically non-existent, which led to incorrect assumptions about the origin of the bones. Although our mental constructs can help us make sense of the world around us, sometimes they can get in the way of our ability to see things as they really are. It seems counterintuitive that to understand the nature of our world, sometimes one has to imagine alternative realities—Cuvier and the espces perdues are an excellent example of this.

We definitely have many instances of this occurring throughout the history of science and I would love to hear of some others that our Fact Finders may find interesting. One that is now relatively old news is the great debate on whether serotonin was a signaling molecule in the gut! Can you believe that Michael Gershon had to fight against other scientists in his field for YEARS, showing experiment after experiment that serotonin was not only being produced in the gut, but that it served a critical role in its function? Today we know that the majority of the body’s serotonin is produced in the gut, but there was once a time where this was unimaginable and it was thought to only be produced and functional in the brain.