Fossil Discovery Pushes Back Timeline for When Mammals First Learned to Chew

New fossil evidence suggests that the ability to chew and swallow food, a capability most people use without a second thought today, emerged in early mammal relatives by at least the middle Jurassic period, a time when dinosaurs still dominated the planet.

The finding pushes back the known timeline for when this basic but biologically significant ability first appeared in the lineage that eventually gave rise to modern mammals.

Why chewing matters evolutionarily

Chewing, unlike simply biting and swallowing food whole, allows an animal to mechanically break down food before digestion, a trait associated with more complex jaw and tooth structures. Scientists studying the evolution of mammals have long been interested in pinpointing when ancestral species developed specialized teeth and jaw mechanics suited to processing food this way.

Fossils from the middle Jurassic period, which occurred roughly in the middle of the age of dinosaurs, offer researchers a window into a time when early mammal relatives were small, often nocturnal creatures coexisting alongside much larger dinosaur species.

Identifying chewing capability in such an ancient specimen gives researchers a clearer sense of how feeding adaptations evolved well before the eventual diversification of mammals seen today.

Further analysis of the fossil and comparison with other specimens from the same era is expected to help refine understanding of exactly how and when this ability developed across different early mammal lineages.