Ants are notoriously efficient undertakers, carrying off dead nestmates before the corpses can infect the colony with their pathogens. Some researchers had hypothesized that ants detected breakdown products in decomposing bodies, but a new study undermines that theory. Entomologists from the University of California, Riverside, found that Argentine ants could detect dead nestmates before decomposition could have taken hold. More telling, the team found that living ants produce two “I'm not dead yet” chemicals, called dolichodial and iridomyrmecin. The compounds curb necrophoresis, the removal of dead colony members by fellow workers. Both chemicals dissipate quickly after death, plummeting to below half strength in just 10 minutes, the researchers write in a paper published in the May 19 Proceedings of the National Academy of Sciences USA.