(CN) – Though carnivorous alligators and crocodiles are known for their sharp teeth useful for digging into animal flesh, some of their ancient cousins may have been herbivores who were content to munch on plant life, according to new research released Thursday.
A study published in the journal Current Biology details evidence that suggests groups of ancient crocodyliforms were herbivores, based on the complexity of their teeth.
"The most interesting thing we discovered was how frequently it seems extinct crocodyliforms ate plants," said study co-author Keegan Melstrom of the University of Utah. "Complex teeth, which we infer to indicate herbivory, appear in the extinct relatives of crocodiles at least three times and maybe as many as six in our dataset alone."
Scientists discovered that the extinct species differed from their more carnivorous cousins by their differently shaped and sized teeth.
"Carnivores possess simple teeth whereas herbivores have much more complex teeth," Melstrom said. "Omnivores, organisms that eat both plant and animal material, fall somewhere in between. Part of my earlier research showed that this pattern holds in living reptiles that have teeth, such as crocodylians and lizards. So these results told us that the basic pattern between diet and teeth is found in both mammals and reptiles, despite very different tooth shapes, and is applicable to extinct reptiles."
The study’s authors compared tooth complexity of the extinct crocodyliforms to those of modern animals. Using dental measurements and structural features, scientists were able to reconstruct the diets of the extinct species.
At least three times throughout history, this ancient cousins showed up prior to the evolutionary form of crocs and gators we know today.
"Our work demonstrates that extinct crocodyliforms had an incredibly varied diet," Melstrom said. "Some were similar to living crocodylians and were primarily carnivorous, others were omnivores, and still others likely specialized in plants. The herbivores lived on different continents at different times, some alongside mammals and mammal relatives, and others did not."
Melstrom said additional research could help scientists understand why these ancient cousins evolved so differently and if their dietary habits contributed to their extinction.
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