The extinct carnivore, Kolponomos, looked like a bear, and bit like a sabre-toothed tiger.
A group of carnivores that went extinct around 20 million years ago looked superficially like modern bears, but new research shows their bite was more similar to sabre-toothed cats. Known as Kolponomos, these extinct bears were thought to feed on shelled organisms, like modern otters, but with few fossils to go on, their diet and lifestyle has remained contentious.
The study, published in Proceedings of the Royal Society B, used 3D biomechanical simulations and jaw-shape analysis, based on skull CT scans, to compare the bite of Kolponomos, Sabre-toothed cats and living carnivores such as bears, wolves and otters. The researchers found that Kolponomos had a similar jaw shape and probably caught prey using a bite-style like that of sabretooths, before using their otter-like back teeth to crush the shell. Both animals used their jawbone as an anchor – the sabretooth using the extra traction to drive their enormous canines into prey, and Kolponomos using it to prise shells from rocks.
Interestingly, although otters and Kolponomos both crush their shelled snacks, they produce the necessary crushing forces in different ways. The team found that Kolponomos‘s jaw is much stiffer than modern otters, more like a brown bear’s jaw. This means that they can easily crush shells, even though their jaws had a relatively low power-output. This is the opposite of the situation in both sea and river otters, who make up for their relatively supple mandibles by producing a very high power output (a high mechanical efficiency). The authors say that Kolponomos and Otters have found different solutions to the same problem, how to live off a food supply that is hidden inside a hard shell.
Want to Know More?
- Tseng, Grohe and Flynn (2016)A unique feeding strategy of the extinct marine mammal Kolponomos: convergence on sabretooths and sea otters Proceedings of the Royal Society B.
Featured image used under a creative commons license from MorphoSource.