Ants are keen on disposing of their dead

Clay Thompson, The Republic | azcentral.com9:37 p.m. MST October 12, 2014



Today's question:

I walk several miles around our neighborhood every day and frequently take long hikes in the desert. During the course of these walks, I see thousands and thousands of ants scurrying back and forth. My question is: Why do I never see even one dead ant? What happens to them?

What would you want with a dead ant?

Sorry, that was gratuitous snarkiness, wasn't it?

The fact of the matter is that ants are very tidy. They keep a clean house, and for the sake of public health they don't want any decaying corpses around anymore than you would.

When an ant dies, two days later its hill-mates pick up the corpse and take it to a sort of garbage dump. Sometimes it's a distant site from the colony or a special chamber far away from the rest of the tunnels.

Why two days? This is sort of morbidly funny. It's because it takes that long for the other ants to realize their buddy is dead.

Two days after an ant dies it begins to give off something called oleic acid, which signals to the other ants that it's time to call in the ant undertakers.

Edward O. Wilson, the famous Harvard biologist, found that if you coat a live ant with oleic acid the other ants will haul it off to the burial site no matter what the living ant has to say about it. That must be discouraging for the little guy.

Now this is kind of interesting: A new species of wasp recently discovered in China uses dead ants to protect its nest, probably because the oleic acid discourages intruders.