Air Date: Week of April 26, 2002

Living on Earth’s Maggie Villiger reports on how Belding's ground squirrels figure out who's closely enough related to be worth risking your life for. There's more than meets the eye to those welcome kisses amongst ground squirrels.

Transcript

VILLIGER: When Belding’s ground squirrels touch noses upon meeting, it’s more than just a friendly hello. New research suggests they’re checking each other out to see who’s worth protecting. These small mammals live in open meadows, making them easy targets for predators. Raising an alarm, or helping fight off an intruder, puts a squirrel at greater risk of death than if she just looked out for number one.

But, from time to time, scientists observed the squirrels acting in these altruistic ways. Nepotism likely explains a squirrel’s decision whether to act. According to evolution, it makes sense to stick your neck out at personal risk if you’re protecting close relatives. Even if you die, most of your genes will be passed on by those relatives.

But in a bustling field filled with other squirrels, how can you be sure who’s close enough to warrant the risk? To find out, researchers presented squirrels with facial gland secretions. The more distant the relative, the longer a squirrel investigated the odor.

Since a squirrel can distinguish between mother, grandmother and cousin, sniffing for these scents explains how she can identify whose genes are close enough to want to protect. In the world of Belding’s ground squirrels, those welcome kisses are really a way to figure out if it’s worth risking your life for this seeming stranger. It gives a whole new meaning to "kissing cousins." That’s this week’s Animal Note. I’m Maggie Villiger.

CURWOOD: And you’re listening to Living on Earth.

[MUSIC: Bedrock woth Kyo, "For What You Dream Of," TRAINSPOTTING (Telstar – 1996)]