Why a woodchuck chucks


Researcher: The world's leading expert on marmot alarm calls says it's `a privilege' to try to understand why the rodents act as they do.

May 27, 2002|By Steve Hymon | Steve Hymon,SPECIAL TO THE SUN

For the past 15 years, Dan Blumstein has been trying to get inside the heads of marmots. This is not an easy thing to do, as some marmots are total head cases.

Blumstein is a professor of animal behavior ecology at the University of California at Los Angeles, a job that asks him to explain why various species act as they do. He's also the world's reigning expert on marmot alarm calls.

Though this may seem an odd line of research -- it's not exactly Gorillas in the Mist -- Blumstein says marmot alarm calls are worth pondering for many reasons. Perhaps the most important is an overwhelming curiosity about how animals perceive the world. Or, to put it another way, he really wants to know why a woodchuck chucks.

"It's a privilege," he says, "to try to understand this stuff."

Groundhogs, also known as woodchucks, are one of 14 species of marmot. Classified as rodents, marmots are close relatives of prairie dogs and ground squirrels.

Blumstein's first serious encounter with the creatures came on a cycling trip in Asia in 1987, when he came across a colony of long-tailed marmots in the mountains of northern Pakistan.

When predators such as foxes or golden eagles were present, the marmots would sometimes issue alarm calls and then hide in their burrows until danger passed.

But what were the marmots saying with their whistle-like calls? Were they shrieking in terror? Telling their mortal enemies to get lost? Or screaming "fox" or "eagle" to other marmots?

The question that really bothered Blumstein: Why would a marmot risk alerting a predator to its whereabouts by whistling? Why not quietly retreat to a burrow?

Finding answers to those questions has required Blumstein to be inventive. As part of an effort to better replicate natural threats, so he could tape-record marmot whistles, Blumstein built a kite that resembled an eagle. Evil KnEagle, he called it.

Explaining this in one scientific journal, Blumstein and Walter Arnold wrote: "We attempted to launch the kite in such a way as to make it suddenly appear over targeted marmots without the marmots seeing the people flying the kite."

Because the kite was sometimes unwieldy, he constructed RoboBadger, a stuffed badger mounted on the chassis of a radio-controlled car. Maneuvering the car through marmot colonies often provoked calls -- and proved science can be a great deal of fun.

Back in his lab, Blumstein used a computer to analyze frequency, tone and length of the chirps, yips, chucks and kee-aws that marmots sounded.

"We didn't have any indication marmots were saying `eagle' or `snow leopard' or `wolf,'" he says. "But they were saying, `I'm scared, I'm more scared, now I'm getting less scared.' So they could communicate in some kind of dynamic way about risk."

Blumstein also spent time studying the social behavior of yellow-bellied marmots with colleague Ken Armitage in the Rocky Mountains near Crested Butte, Colo. Armitage, a University of Kansas biologist, has carefully tracked this marmot colony every summer since 1962 -- making it one of the longest continuing studies of a mammal population.

"One of the fundamental questions that has emerged from our work is: Why do marmots decide to alarm call when they do?" says Armitage. "Because we know they don't always call when there are threats."

When danger lurked, marmot mothers would sometimes whistle to warn a daughter, but not an aunt, uncle or niece. There were other strange behaviors. Mothers prevented daughters from reproducing. Infants were killed. Permanent expulsions from the colony were common.

In short, the colony of cute, fuzzy creatures resembled Peyton Place more than Disneyland.

In papers written over the past decade (many with Armitage and other researchers), Blumstein has focused on two key findings:

In yellow-bellied marmots, whistles are often intended to protect offspring. The whistles are an individual's way to ensure that its genes dominate future generations. Conversely, getting rid of genetic competition may be the reason marmots do not whistle to a distant relative about to become coyote chow.

"The name of the game is maximizing the number of your genes in future generations," Blumstein says. "Mathematically, it makes perfect sense."

His work also suggests that species of marmots with the most socially complex colonies also have the most elaborate whistles. In other words, the marmots that survive in a complex world may be the ones that can communicate.

"Part of the study of evolution is understanding the different ways species solve common problems," Blumstein says. "Everyone has to eat, reproduce, sleep, hunt, protect their young. Some monkeys have different calls referring to different species. Marmots don't have a single word. That just goes to show there are different ways to solve a problem."

There is also a more practical side to Blumstein's work, because understanding how an animal behaves is often the key to conservation of a species.

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