When you think of Sabertooth cats, you probably picture the legendary Smilodon fatalis, which has massively elongated canine teeth and is best known from specimens found in the La Brea tar pits in Southern California. (Smilodon fatalis fossils were also found in Nashville, Tennessee – which led to the name and mascot of the NHL’s Nashville Predators ice hockey team.)
However, the cat that once occupied all continents except Australia and Antarctica is the homotherium with the scimitar teeth. This cat’s teeth were flattened and less elongated, but it was still a formidable predator.
According to a new study conducted by paleontologist and associate professor of life sciences Larisa DeSantis and published April 15 in the journal Current Biology, Homotherium had a unique ecology that involved the consumption of prey in open grasslands. Among the prey were mammoth babies.
The artistic reconstruction of homotherium-consuming juvenile mammoths by co-author Mauricio Antón is based on a detailed study of homotherium fossils. (Mauricio Antón)
“Clarifying the relationships between predators and prey in the ancient past can provide insight. . . Conservation and management of the apex predators living today – including lions, tigers and polar bears, ”DeSantis said.
Ernest Lundelius Jr. (left) and Larisa DeSantis (right), two of the study’s co-authors, examining fossils in Texas.
One of the most remarkable Ice Age fossils in the world is the Friesenhahn Cave, a site outside of San Antonio. Along with an abundance of Homotherium specimens, numerous prey species (including a variety of juvenile mammoths) led to the formation of the “Homotherium den” hypothesis – that these cats brought their prey back to the den to be consumed. DeSantis’s team of researchers integrated data from stable isotopes, the analysis and morphology of dental microcloth textures – the branch of biology that studies the shape of living organisms and the relationships between their structures – to reconstruct the ecology and biology of Homotherium.
“Morphology can give us an initial approximation of nutrition and behavior, and in the case of Homotherium, this suggests that it is a unique predator. It really was a cat like no other, despite resembling cheetahs and hyenas, ”said DeSantis.
“Features such as the derived, partially retractable, small claws and graceful forelegs indicate that Homotherium was moderately italic,” said Mauricio Antón, co-author of this study, world-renowned scientific illustrator and Homotherium expert at the Museum of Natural Sciences in Madrid. “But unlike cheetahs, which have brief bursts of high speed, homotherium likely continued to run longer, although probably not as fast as live cheetahs.”
Homotherium was also different from the Smilodon fatalis in that it preferred prey with a more open habitat based on the specimens in the den (including large numbers of approximately 2 year old baby mammoths) and data from Homotherium’s teeth.
“As the saying goes, you are what you eat. In the case of fossils, we can study the chemical makeup of their teeth and determine whether they consumed prey in grasslands or forests or both, ”DeSantis said. “In our study, the stable carbon isotope data of Homotherium’s tooth enamel was indistinguishable from that of baby mammoths, while it was also consistent with the consumption of other mainly open prey such as bison and horses.”
Surface structure of the dental microclothes of Homotherium Serum (TxVP 933-2456) from the Friesenhahn Cave in Texas, indicating the consumption of tough and soft meat, but no significant bone processing. (Larisa DeSantis)
In addition to examining the chemical signatures in their teeth, the researchers also examined the microscopic wear patterns that arise when chewing. This study found that Homotherium not only avoided bones, as modern cheetahs do today, but also ate harder food than any live cat studied – in line with the consumption of the tough meat of baby mammoths.
“Our study essentially confirmed that homotherium was an open-habitat predator that fed on baby mammoths,” DeSantis said. “While it is likely that Homotherium also ate forest prey, it is also clear that Homotherium had a clear preference for prey with open habitat.”
“This is the first study to show that homotherium ate mammoths. It is a unique result and represents breakthroughs in our knowledge of homotherium, ”said Julie Meachen, Associate Professor of Anatomy in Medicine and Health Sciences at Des Moines University who was not involved in this study.
“It is difficult to study carnivores when carnivores are naturally rare in the fossil record,” DeSantis said. “Sometimes we can examine carnivores from tar seeps, like the La Brea tar pits. In other cases, we’re just lucky and able to examine apex predators from amazing cave areas such as the Friesian Cock Cave. “
“Friesenhahn Cave is a jewel of a fossil site,” said Ernest Lundelius Jr., Professor Emeritus at the University of Texas-Austin and co-author who published on the site in the early 1960s. “In addition to the large animals like Homotherium, we can learn a lot from the other co-existing animals in the cave.”
The research was made possible by the National Science Foundation and supported by Vanderbilt University.
