What happens to dead ants?

Oh, Matthew Alice:

My gears turn in wonder when I see ants and one of them has a dead fellow ant in its jaws. Why do they carry away these dead ants? Where do they take them? What does it all mean?

-- Sitting and Pondering (in Alaska, maybe, judging from the postcard)

Death and bereavement in the ant world are more chemical than cosmic. I'll give you the facts. You sort out the philosophy. Two things to keep in mind -- (1) about 90 percent of all communication in antdom involves chemical signals, and (2) ants are very tidy. An ant that's wounded in the line of duty exudes alarm chemicals that incite the other ants to rally to its aid. If they arrive on the scene and brother ant isn't moving, they don't have to nudge him with their toes or feel for a pulse. They know he's dead because he smells dead. That's a whole different set of chemicals that starts accumulating as soon as the ant bites it. Death pheromones stimulate the other ants to pick up the body and lug it back to the nest. Actually, it goes to the trash heap near the nest. Each colony has its own landfill area full of debris from their tunnels and the corpses of former members. Why are ants so tidy? Science is working on an answer, I'm sure.

Science guys tested ants' response to death chemicals by putting some on pieces of paper. Dutifully, the ants carried the paper away to their garbage dump. Weirdest of all, when they put the smell on a healthy ant, it played dead, his friends carried him off, and once they left, he licked all the smell off him and went on about his anty business as if nothing had happened.