Turtle Ant

Intruders don't stand a chance against a soldier Turtle Ant. She guards the opening to the colony's nest using her shield-shaped head as the door. Only nest mates who smell like her and know the "secret knock"—a rhythmic tap on her noggin with their antennae—will be allowed to enter. Turtle Ants live in hollow twigs of trees. They forage for sap or suck the "honeydew" from aphids that they raise and milk like cows. When knocked from a branch, these ants have mastered the knack of gliding gracefully to the ground like a paratrooper.

Field Museum scientists are currently studying ants and their DNA to learn how they've evolved over time. Researchers have discovered that as lush forests appeared, some species like Turtle Ants adapted by becoming "vegetarians." Special gut bacteria helped them digest plant sugars and provided a source of protein. But as forests shrank, some of these species disappeared, affecting other animals in the food chain. Understanding how climate change impacts ant diversity enables scientists to better predict how related insects may respond to the current environmental challenges we face.