A groundbreaking study published in Evolution on July 19, 2025, maps the rise of myrmecophagy—mammals that exclusively eat ants and termites—revealing at least 12 independent origins since the Cenozoic era began 66 million years ago. From giant anteaters to numbats, these species evolved specialized traits like long, sticky tongues, claw-like hands, and toothless or reduced-tooth mouths to devour thousands of social insects daily. The research, led by Phillip Barden at the New Jersey Institute of Technology and Thomas Vida at the University of Bonn, compiled dietary data for 4,099 mammal species, drawing from 600+ natural history records, conservation reports, and taxonomic datasets.
The trigger? The K-Pg extinction event, which wiped out non-avian dinosaurs and reshaped ecosystems, allowing ant and termite colonies to explode in number and biomass. Today, over 15,000 ant and termite species outweigh all wild mammals combined, but 145 million years ago, they were less than 1% of insects. By the Miocene, ~23 million years ago, they hit 35% of insect specimens, fueled by flowering plants and the Paleocene-Eocene Thermal Maximum’s warm climate ~55 million years ago. “Ants and termites became a buffet,” Barden quipped, noting their biomass drove mammals to evolve extreme feeding strategies.
The Myrmecophage Makeover
Only ~20 of the 200+ mammal species that eat ants and termites are true myrmecophages, relying solely on these insects. Think aardvarks slurping 50,000 termites nightly or numbats gobbling 20,000 daily, despite their low caloric yield. These mammals sport ecomorphological adaptations—specialized claws, sticky tongues, and stomachs built for insect digestion—that make the leap from general insectivory or carnivory a “major barrier,” per Vida. The study sorted species into five dietary groups (obligate myrmecophages, general insectivores, carnivores, omnivores, herbivores) using gut analyses and field observations, then mapped them onto a time-calibrated mammal family tree.
Statistical models revealed myrmecophagy evolved at least once in each major mammal group—monotremes (e.g., echidnas), marsupials (e.g., numbats), and placentals (e.g., pangolins)—but unevenly. Insectivorous ancestors were three times more likely to make the shift than carnivorous ones, with Carnivora (including aardwolves) accounting for 25% of origins. “Going from eating a deer to 300,000 termites a day is wild,” Barden said on X, hinting at physiological traits like malleable dentition easing the transition.
A One-Way Evolutionary Bet
Once mammals go myrmecophagous, they rarely turn back. The study found only one exception: the elephant shrew genus Macroscelides, which shifted to omnivory after adopting myrmecophagy in the Eocene. Eight of the 12 origins are single-species lineages, like the aardvark or silky anteater, showing limited diversification. “It’s a niche that locks you in,” Barden noted, suggesting specialization paints species into an evolutionary corner. Yet, with ants and termites dominating global biomass—over 10 quintillion ants alone—these mammals thrive on a reliable food source.
The study ties the rise of myrmecophages to ant and termite colony expansion, likely spurred by ecological shifts like flowering plants diversifying insect diets. Posts on X, like @BioBlitz’s, call it “evolution’s ultimate hustle,” noting how mammals “bet big on bugs” post-dinosaur collapse. But the strategy’s risks are clear: climate change favors invasive social insects like fire ants, potentially boosting myrmecophages, but their hyper-specialization could spell trouble if ecosystems shift.
Broader Implications
The findings illuminate convergent evolution’s power, with unrelated mammals like pangolins and anteaters developing near-identical traits to exploit the same niche. The study’s dataset, covering 4,099 species, is a treasure trove for future research, revealing dietary diversity from krill-eating seals to sap-drinking primates. It also underscores social insects’ outsized ecological impact, shaping not just mammals but plants and other animals. “Ants and termites are the real MVPs of the Cenozoic,” a Reddit thread quipped, echoing the study’s claim that their biomass drove a “cascade of evolutionary responses.”
