Mammals Have Evolved Ant- and Termite-Eating Adaptations at Least 12 Times Since Dinosaur Extinction

Since the extinction of non-avian dinosaurs 66 million years ago, mammals have independently evolved specialized adaptations for feeding on ants and termites at least 12 times. This finding, published in Evolution by researchers at the University of Bonn, highlights the profound influence of social insects on mammalian evolution.

In the rainforests of Central and South America, the combined biomass of ants and termites exceeds that of all other insects, mammals, amphibians, and birds. Globally, the biomass of termites alone is estimated to be 10 times greater than that of wild mammals. This abundance has repeatedly driven the evolution of ant-eating traits—such as elongated sticky tongues, reduced dentition, and powerful forelimbs—across diverse mammalian lineages.

Analyzing dietary data from nearly 4,100 mammal species, the team found that ant and termite specialization emerged multiple times after the Cretaceous–Paleogene boundary, spanning three major mammal groups, including marsupials and egg-laying monotremes.

This pattern is a striking example of convergent evolution, akin to "carcinization" in crustaceans, where crab-like forms evolved independently multiple times. Yet the pace is remarkable: while crustaceans have undergone carcinization five times over hundreds of millions of years, mammals have developed myrmecophagy at least 12 times in just 66 million years. The shift also appears largely irreversible—only the short-eared elephant shrew is known to have abandoned its ant-eating diet.

The rise of myrmecophagy likely coincided with a post-dinosaur surge in ants and termites, whose ecological dominance grew from roughly 1% to 45% of insect biomass, possibly driven by the spread of flowering plants. At the same time, termites evolved large, stable colonies, providing a dependable food source for specialized predators.

This evolutionary pressure may also have shaped the insects themselves. In response to mammalian predation, ants and termites may have evolved larger colony sizes or enhanced defense mechanisms. The study suggests that evolution continues to push mammals toward ant and termite specialization, indicating that these social insects will face ongoing survival challenges well into the future.