Smell and Self-Defense

Ah, spring in North Georgia. The birds perform a symphony for us each morning.* The crocuses, tulips and daffodils are up. Buds are swelling on the trees, and dormant perennials are bursting from the ground. And there are dead squirrels every hundred yards or so, on all suburban streets.

If I were to examine the hindquarters of this roadkill, which I do not intend to do, I suspect most would be male. The male of the species, who would gladly dash across I-75 in pursuit of some faint pheromone he’s detected from a female, is blinded by lust, a.k.a. his species’ urge to pass his genes on. But that’s all that ever gets these bushy-tailed rodents, so far as I can tell.

Any hardware store, garden center or home improvement superstore will carry about 30 different kinds of squirrel-proof bird feeders. None of these work. You might as well open the bag of seed and dump it on the ground. Every day, in every way, the squirrels outwit us. Coat the seed with cayenne pepper? They develop a taste for hot food. Place the feeder far from the trunk? They hang like monkeys, by their tails, from the supporting branch. I’ve even seen them work cooperatively to defeat our efforts; one digs the food out of the tiny opening, designed for small birds; the other gobbles it below. And then they trade places.

I’ve finally given up, and named the two that live in my trees “Frick” and “Frack”. Both are extraordinarily healthy, white-bellied, and as fat as Jabba the Hut. Soon they’ll be making more squirrels, and will teach them where the food is.

Consider this: apparently, at least in California (where everything happens first) squirrels have been discovered rubbing themselves with shed rattlesnake skins so they will smell like snakes, thereby warding off one of their most common predators. Here are the most salient points from the ScienceDaily newsletter’s story, titled “Squirrels Use Old Snake Skins To Mask Their Scent From Predators”:

California ground squirrels and rock squirrels chew up rattlesnake skin and smear it on their fur to mask their scent from predators, according to a new study by researchers at UC Davis.

Barbara Clucas, a graduate student in animal behavior at UC Davis, observed ground squirrels Spermophilus beecheyi) and rock squirrels (Spermophilus variegates) applying snake scent to themselves by picking up pieces of shed snakeskin, chewing it and then licking their fur.

The scent probably helps to mask the squirrel's own scent, especially when the animals are asleep in their burrows at night, or to persuade a snake that another snake is in the burrow.

The squirrels are not limited to the use of shed snake skins, said Donald Owings, a professor of psychology at UC Davis who is Clucas' adviser and an author on the paper. They also pick up snake odor from soil and other surfaces on which snakes have been resting, and use that to apply scent.

"It's a nice example of the opportunism of animals," Owings said. "They're turning the tables on the snake."


Occasionally I find shed snakes’ skins in my yard. Hmmmm….oh, forget it. I know when I’m licked.


*well, not exactly; they’re single males screaming for a partner so they can reproduce.


Citations and links:

The complete text of the article may be found at ScienceDaily.com


Photo courtesy of FreeDigitalPhotos.net

The other authors on the paper, which was published Nov. 28 in the journal Animal Behavior, are Matthew Rowe, Sam Houston State University, Texas, and Patricia Arrowood at New Mexico State University. The work was funded by the National Science Foundation and the Animal Behavior Society.