With recent archaeological findings proving that researchers may not know as much about prehistoric life as they once thought, researchers with the American Museum of Natural History are taking another look at interpreting the diets of long-extinct animals, and what they're finding points to finding the source of a prehistoric diet. Though teeth shape has been used for decades as a primary indicator as to the dietary habits of a fossilized subject, in a new study published today in the journal PLOS ONE, researchers are now saying that skull shape and ancestral lineages, both before and after extinction events, may serve as a proxy for what these animals truly once ate.

Led by American Museum of Natural History researchers, John Flynn and Zhijie Jack Tseng, the new study investigated the role that skull shape and biomechanics play into models revealing whether or not a dinosaur or long extinct species was a carnivore or more of an omnivore instead. Initially the results indicated that diets largely met biomechanical demands, but when they started to factor family lineages into the mix, they also realized that ancestry was a large factor too. Together not only could researchers gleam a possible dietary preference, but they could also learn a lot about feeding strategies.

"Traditionally, when we looked at a fossilized skull with pointy piercing teeth and sharp slicing blades, we assumed that it was primarily a meat eater, but that simplistic line of thinking doesn't always hold true" Flynn says. "We've found that diet can be linked to a number of factors-skull size, biomechanical attributes, and often, most importantly, the species' position in the tree of life."

Though initial modeling allowed researchers to map bite force and improve shape-function to currently existing computer models for early carnivores, they believe that with the knowledge they have gained that they can learn so much more. By interpreting then, not only the shape of the skull but also its biomechanical strength, researchers can better guess what size prey or even what type of meat/fruits and vegetables an extinct species may have eaten. So even though they may have a long way to go to describe the diets of all animals, they can better identify at least what sorts of foods dinosaurs and the extinct may have once had on their plates.

"Beyond feeding adaptations of extinct species, we also want to decipher how adaptations evolved using reconstructed ancestors of living and fossil forms" Tseng says. "We are applying similar types of skull shape and biomechanical analyses to reconstructed hypothetical ancestor skulls of Carnivora and their relatives to map out and better understanding the long history of feeding adaptation of living top predators."