When ants of the species Temnothorax unifasciatus get sick, they abandon their nest, walking far away from their relatives to die alone

They perform this act of heroism to prevent the illness that is killing them from spreading to the colony. The discovery is the first time that such behavior has been shown in ants or any other social insect. Researchers decided to investigate the ants' behavior after becoming interested in anecdotal reports of dying individuals deserting their families. Such behaviour has been reported in dogs, cats, elephants and even people. But because it happens occasionally, it cannot be quantifiably studied. The researchers decided to set up an experiment to study the phenomenon in ants, which they also noticed would occasionally leave the colony for no apparent reason. The scientists exposed a colony of Temnothorax unifasciatus ants reared in their laboratory to the spores of a lethal parasitic fungus called Metarhizium anisopliae. Most of the workers who died from the fungal infection permanently left the nest hours or days before death, and died in a foraging area far from their nest mates.