Newly Discovered “Paramedic Ants” Tend to and Heal Their Wounded Comrades

Most of us don’t think a great deal about ants as we go about our daily routines, although we know they’re capable of some pretty impressive feats, such as the intricate tunnel networks they construct. And it turns out at least one species of ant has even more tricks.

National Geographic reports that myrmecologist (that means the study of ants) Erik T. Frank has observed some remarkable and previously-unknown behavior from matabele ants, a species that’s native to sub-Saharan Africa. It seems that after these insects raid termite colonies, they actually carry home their wounded ant brethren, then treat their injuries — taking turns holding the damaged limbs in place and “licking” the wounds.

“I did not think the ants would have such a sophisticated treatment of the injured—or that it was actually necessary,” explained Frank, whose paper in Proceedings of the Royal Society B details behavior that’s unprecedented in the animal kingdom.

Frank and colleagues at the Comoé National Park Research Station in northeastern Côte d’Ivoire created artificial nests topped with a clear cover so an infrared camera could capture the action inside.

They saw that once in the nest, the ants carefully examine injured comrades, probing them with their antennae more than twice as often as healthy nest-mates.

This behavior proved vital: 80 percent of experimentally injured ants died within 24 hours if kept by themselves. But if cared for by their nest-mates for even an hour, only a tenth died. Interestingly, 80 percent survived without treatment if placed in a sterile environment, so Frank believes infections are the main cause of death and this “licking” behavior may help prevent them.

But that’s not even the craziest part. It seems both the injured and their would-be rescuers prioritize aid to those who can be nursed back to health, and leave to die those whose injuries are too severe. Injured ants release a pheromone alerting their brethren that they need help, as well as play up their injuries by intentionally stumbling. Dying ants, meanwhile, will actually prevent comrades from helping them by flailing their limbs around to block assistance.

“In humans in cases were a triage system is necessary, the decision [about] who will receive help is made by the doctor: a top-down regulated system,” Frank observed, but when hit comes to these ants “it’s exactly the opposite.”

Helen McCreery, a postdoctoral fellow at Michigan State University who studies social behaviors in ants, found the paper exciting, even though the behavior makes evolutionary sense. “What’s the point in rescuing your nest-mate if they won’t survive anyway?” she asked. “Still, when I read that they bring wounded ants home, I didn’t imagine they would treat the wounds.”

There’s a lot left to learn about why, when, and how social insects may try to rescue one another, she said. “It’s quite likely that there are other ant species, or other social insects, that tend to their wounded.”

Absolutely fascinating. But what do you think about all of this? Share your thoughts in the comments below!

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