According to a recent survey by the Gates Foundation, crocodiles and alligators, the much-feared carnivores, kill at least 1000 people every year.
Still, new research suggests that the ancestors of these reptiles may have been vegetarians at some point in their evolutionary history which stretched for over 200 million years. According to the said research, while some crocodile relatives were semi-aquatic and are ambush predators during the Mesozoic Era, other crocodiles thrived on land with a more omnivorous palate.
Keegan Melstrom from the University of Utah, and Randall Irmis, the chief curator for the Natural History Museum of Utah, worked together on a new research paper which was recently published in the journal Current Biology. According to their research, there is more evidence that the ancient group is known as crocodyliform, a group from which modern reptiles have descended, have adapted both omnivorous and herbivorous diets.
For the study, the authors of the paper conducted a thorough analysis of the fossilized crocodyliform teeth that they have access to. Their team of researchers has studied a total of 146 fossil teeth from 16 different extinct species of the said reptile group. They have used high definition, three-dimensional tooth-mapping. This process has led the researchers to get a glimpse of the diet structure of ancient crocodyliforms.
Irmis stated that as their team has seen different tooth shapes in the history of reptile evolution, some were recorded to be fairly straightforward. However, there was no comparison for some of the others. The scientist added that some of the crocodiles that people thought of as strict herbivores are more likely to be insectivores and omnivores.
Melstrom cited a surprising discovery from their research data which have shown that the Notosuchus crocodile from Argentina, which was previously thought to be a herbivore, has now been recently revealed as a carnivore.
The research has shown a different angle and more insight into how an environment can affect the evolution of a species. However, the effects of the environment on evolution is not always a straight line. For example, some reptiles that have evolved into herbivores did not do so just because herbivorous mammals are absent and the current herbivorous reptiles needed to fill a niche.
Melstrom added that there is no need for a single special environment for such an evolution to happen. It largely depends on the dietary strategy of the species as well.
