Crocodiles found these days are known to be carnivores that depend on flesh, however, it wasn’t the case with very ancient crocodiles as they were vegetarians and preferred leafy greens, as per a new study.

According to a new research based on teeth fossils that still exist long after even these ancient crocodile species went extinct, crocodiles earlier favored plants over flesh and were said to be vegetarians, unlike today’s crocs.

The study published in Current Biology stated that ancient crocodyliforms – group from which modern day reptiles including crocodiles, alligators, caimans, and gharials are descended – were more different over the course of their evolutionary behavior, wrote Gizmodo.

Using HD 3D-mapping and computer models, the study involved 146 teeth across 16 unique relatives of the modern day crocodile. Since certain traits of teeth of ancient species such as size and shapes can give clues about the animal’s diet, the team concluded that many of the species were born herbivores and plant-eaters, reported BGR.

“Carnivores possess simple teeth whereas herbivores have much more complex teeth,” lead author Keegan Melstrom. “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.”

However, the team is still not sure what set these crocodiles apart and what environmental conditions might have prompted the species to turn into the scary beasts they are today. Yet, the team hopes to better understand these factors in coming time.