Ants know how to ‘perform surgery’ to save their kind

Ants in Florida can perform life-saving surgery on their fellow ants, according to research published July 2 in the journal Current Biology. They are the second animal in the world to have this ability, after humans. Researchers discovered that Florida carpenter ants (Camponotus floridanus) Identify the wound on the leg of the nestmate, then treat it by cleaning or amputating.

“As far as amputation goes, this is the only case in which an individual performs a complex and systematic amputation on another member of the same species in the animal kingdom,” concluded study lead author Erik Frank, a behavioral ecologist at the University of Würzburg in Germany.

In 2023, Frank’s team discovered that a species of African ant called Megaponera analis can treat infected wounds on its colony members with antibacterial compounds secreted from its glands. Florida carpenter ants don’t have similar glands, so the team wanted to learn how they treat the wounds of their fellow carpenter ants.

Specifically, the researchers looked at two types of leg wounds: thigh lacerations and leg lacerations. In the experiment, they observed carpenter ants treating thigh lacerations by cleaning them with their mouths and then amputating the leg by biting repeatedly. Meanwhile, they only cleaned leg lacerations. The surgery significantly improved the survival rate of patients. The survival rate for thigh lacerations increased from less than 40% to 90-95% after amputation, while the survival rate for leg lacerations increased from 15% to 75% after cleaning.

Scientists believe that the ants only amputate thigh wounds rather than all leg wounds due to speed limitations. The ants take at least 40 minutes to complete the amputation. After studying CT scans of carpenter ants, Frank and his colleagues speculate that damage to the thigh pumping muscles slows blood circulation. This would make it take longer for the bacteria-laden blood to circulate throughout the body, allowing the ants enough time to amputate the limb.

In contrast, ant stings have relatively little muscle tissue, so infections can spread more quickly. This means carpenter ants spend too much time amputating limbs to prevent harmful bacteria from spreading, so they focus on cleaning the wound. “Ants can diagnose a wound, see if it’s infected or sterile, and treat it accordingly over the long term. It’s the only medical system comparable to humans,” Frank says.

The ability to recognize and treat wounds in ants is innate, and the researchers found no evidence of learned behavior. They are now expanding their research to other species of ants that do not possess special antibacterial glands to see if they are also capable of performing surgery.