Squirrels Network Like Facebook Friends

Feb. 21, 2008 -- The squirrel world has its own Kevin Bacon -- a socially well-connected individual dubbed Mercedes by the scientist who studies him.

The major difference between human and squirrel social networks is that people, as the conventional wisdom goes, appear to be "separated" by five or six degrees. For squirrels, it takes only three connections for one member of a population to get to any other.

"It's the same thing," said Theodore Manno, a biologist at Auburn University in Alabama. "Squirrels with many connections tend to befriend squirrels that are like them; squirrels without many connections tend to befriend squirrels like them as well."

"Isn't that the same as the popular crowd going to each other's Facebooks and the skater kids doing the same?" he asked.

The discovery that squirrels have social networks not only illustrates the complexities of animal behavior, but also says something about the properties shared by all networks.

Manno pursued the idea after F. Stephen Dobson, also at Auburn University, suggested that network theory could be applied to social interactions within a squirrel colony.

Manno observed 65 wild, free-ranging Columbian ground squirrels in Sheep River Provincial Park in Alberta, Canada. After naming and taking notes on each squirrel, Manno watched and recorded details about their social behaviors -- including "kissing" (oral contact that doesn't lead to bickering), sniffing, playing and grooming.

Over the course of the study, which will be published in the April issue of Animal Behavior, Manno observed 2,200 such interactions. Using a software tool called UCINET that has identified networks among airplane hubs, bridge supports, the Internet, human and animal societies and more, he charted connections between the squirrels.

Mercedes, for example, was linked to the squirrels 7-Up, 3-Cherry, Eighth Notes and Princess Pea.

Most of the connections were between mating squirrels and their families. But friendship, too, exists in the squirrel world, said Manno. He even has a way to measure it.