Have Crocodiles Always Been Carnivorous?

There are many types of creatures that have been part of the crocodile family over the centuries. Today’s large, four-limbed crocs continue to thrive on a carnivorous diet, but many of their ancestors -- those “herbivorous crocodyliforms” that preferred plant-based diets -- didn’t survive the mass extinction event that wiped out nearly all lifeforms on Earth around 66 million years ago. By studying fossilized teeth of ancient crocodile-like reptiles, scientists have determined that three independent groups of ancient crocodyliforms went vegetarian throughout the long course of evolution, probably about 200 million years ago.

What big, sharp teeth you have:

• Scientists say that meat-eating predators have teeth “that look like steak knives -- thin and sharp, straight and simple, with no frills.” Plant eater teeth have “nooks and crannies” used to grind the various plant parts.
• All terrestrial crocs have gone extinct, not just the herbivores. The two dozen species on Earth today live near lakes, rivers, and seashores, where they can hunt for meat and fish.
• Modern-day crocs are not strict carnivores, though. Many species have been known to eat fruit occasionally, sometimes plucked right off trees.