Today’s factismal: The common tree squirrel can rotate its back ankles 180° in order to climb down a tree head-first.
Squirrels are fun, frolicsome, and fascinating critters. They jump from limb to limb in search of nuts and acorns that they bury in profusion and they crawl on the forest floor hoping to find some tasty insects, slugs, and small birds, or snakes.Because they move from climbing up to climbing down to crawling around with such frequency, they have developed some special adaptations. Perhaps the most interesting of these is their back ankles which rotate 180°; in effect, they can put their feet on backward. Though that would make them a little awkward if they did it on the ground, it is perfect for when they want to head down a tree head-first.
But why would a squirrel want to go head-first down a tree? Because squirrels have a lot of things that like to feast on them. By going down head-first, they can keep an eye out for snakes, birds, raccoons, and automobiles to name but three. Automobiles are particularly deadly; the jerky, back and forth evasion pattern that gray squirrels have evolved to escape from predators in a forest makes it very hard to automobile drivers to avoid hitting the poor beast. As a result, the leading cause of death for gray squirrels in a city is being run over.
Despite their predator problems, squirrels remain plentiful. In part, that’s because of their fecundity. Tree squirrels become sexually mature at six months and a female can have two litters of two to six baby squirrels each year. As a result, even though they only live a short time, squirrels are in no danger of dying out. But they do provide biologists with a puzzle: where do they live? What do they eat?
And the biologists would like your help in solving the puzzle. All it takes is a pair of binoculars, a few hours, and a willingness to spy on our tree-dwelling neighbors. If you’d like to help, then why not join Project Squirrel? http://www.projectsquirrel.org/