How Ants Bury Their Dead
DEBBIE ELLIOTT, host:
We take a turn now from science in the jungle to Science out of the Box.
(Soundbite of music)
ELLIOTT: Did you know some ants stacked their dead comrades in neat compact little burial mounds? Scientists are fascinated and are seeing what they can learn from this.
NPR's John Nielsen has gone to see for himself and he's just called in from what he says is a big chamber in the middle of an ant colony. John, are you there?
JOHN NIELSEN: Yeah, but you got to be quiet because it's a funeral. It's just getting started. Specifically, it's a harvester ant funeral; that's why I'm deep inside the colony right now.
ELLIOTT: What's the scene there?
NIELSEN: The scene is that the queen is about to deliver her eulogy and these are very, very dramatic eulogies. In fact, I'll just turn the phone so you can hear it.
Unidentified Woman #1: We come together today to celebrate the life and mourn the sad loss of our dear departed colleagues. Hard workers all...
NIELSEN: It's really sad, isn't it. It's powerful.
ELLIOTT: Now, how did these ants die, John?
NIELSEN: They were fried by a kid with a magnifying glass, apparently.
ELLIOTT: Okay, John, I don't think I can follow you anymore. You're not really in a middle of an ant colony, are you?
NIELSEN: I couldn't really keep this going much further either. No, I'm not. I'm not in an ant colony. I'm in a studio upstairs from you.
ELLIOTT: But you do have something to tell us about ants?
NIELSEN: Yeah. I do, I do. Here's a story. It's about why computer scientists and traffic engineers and people who build robots are all so interested in the way living ants deal with dead ones. It's true that ants don't have funerals and they don't give speeches at these funerals, but they do have underground cemeteries, sort of.
And they do stack their dead in all kinds of interesting ways. For example, let's go back to those harvester ants we were juts pretending to listen to. They stacked dead bodies up in intricate little piles that get rearranged on a more or less constant basis.
I got that from Deborah Gordon, who is an ant expert at Stanford University, and she ought to know because she spent a good part of the last 20 years watching harvester ants make those stacks. And in fact she finds them weirdly attractive.
Ms. DEBORAH GORDON (Stanford University): It might be like a little triangle-shaped pile with a little bits of grass that the ants have cut, and husks of seeds and a few dead bodies. And then the next day they'll pick it all up and pile it somewhere else, and the next day they move it back.
NIELSEN: Gordon says this carcass sorting is one of many complicated tasks that get performed by ants. They find their way around inside incredibly complicated underground cities. They find scattered bits of food and bring it all back to the colony. And they fight huge wars with other ant colonies.
And here's what makes all of these really interesting. If scientists can figure out how ants do some of this stuff - if, for instance, they could figure out how ants stack their dead - they could use some of that knowledge to help us understand and maybe solve some familiar human problems, like this one.
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Unidentified Woman #2 (Operator): All circuits are busy now. Please try your call later.
NIELSEN: Or this one.
Unidentified Woman #3: Closed at 29 are Nash Street and Fort Meyer Drive. Outbound key bridge traffic must go south on the Lee Highway.
NIELSEN: The phrase you want to remember here is swarm intelligence, okay? Swarm intelligence. Scientists say that's the phenomenon that links ants to jammed-up phone lines and traffic nightmares.
Swarm intelligence holds that if you take a lot of individuals and programmed them to follow the same basic rules, you can get incredibly complicated group behaviors out of the process, like stacking your own carcasses in little triangular piles and moving them around all the time.
Stanford's Deborah Gordon says the simple rule at work here could be something like pick up your dead ants and carry them around in your mandibles until you run into more dead ants, and then drop yours.
Now, Gordon says it might be hard to follow this idea if you think ants follow orders. They don't.
ELLIOTT: Nobody directs the behavior of the ants. The queen doesn't tell anybody what to do. Unlike the way it works in the movies, there's no foreman or bureaucrats or managers. So the question is, how does the colony manage to accomplish anything?
NIELSEN: Gordon says the answer to this question is that ants have been genetically coded to do many of the things they do. She adds that non-biologists have been spending lots of money in an effort to decipher these codes.
Mr. TAYLOR BULCH(ph) (Georgia Institute of Technology): So this is the lab where we keep the ants. These are desert ants. And...
NIELSEN: Computer scientist Taylor Bulch is one of those non-biologists. He raises colonies of desert ants on very big tables in a very hot room at the Georgia Institute of Technology in Atlanta.
Mr. BULCH: Where's our water squirter? Oh, here we go.
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NIELSEN: He films these groups of ants whenever they're up to something. Then he feeds his films into computers that attempt to find the basic rules behind particular behaviors.
Mr. BULCH: And the approach to my research is to say, well, let's pretend that these ants are robots. Can we figure out what their program is?
NIELSEN: And one of the reasons Bulch looks for these programs is because he's got a lab next door to this one, and in that lab he's attempting to build robots that act like ants.
Mr. BULCH: Here's an example of some of the robots we use.
NIELSEN: Bulch says a team of robots built to use swarm intelligence would have all kinds of potential uses, like searching and rescuing or fighting battles.
Mr. BULCH: I could imagine it being used to arrange mine fields in particular patterns.
NIELSEN: And, he says, if you can build robots that act like ants, you might be able to build more efficient phone networks or better traffic control systems. But Deborah Gordon of Stanford University says there are some ant behaviors that we might not want to copy. For example, sloth. Gordon says nearly half the ants she sees inside her colonies looked extremely lazy.
Ms. GORDON: Contrary to what it says in the Bible, you know, look to the ant thou sluggard and all that - most of the ants inside the nest are just hanging around doing nothing.
NIELSEN: This is not a form of swarm intelligence that's likely to be studied at great length anytime soon, Gordon says. After all, we're already really good at it.
John Nielsen, NPR News, Washington.