Thanks to cartoon characters such as Bugs Bunny, the rabbits we see in our backyards -- eastern cottontails -- are familiar to almost everyone. And yet I suspect that most people think they are rodents. They are not. Rabbits and hares are lagomorphs, members of the mammalian order Lagomorpha.
The confusion is understandable. Both groups are herbivores, and their skulls are superficially similar. Each has a large gap between the incisors and molars, but a closer look at a lagomorph skull reveals two key differences.
First, lagomorphs have two pairs of upper incisors. A small peg-like pair sits behind the much more conspicuous front pair. Rodents have a single pair of incisors. Second, the cheek bones of rabbits form a mesh-like network of bone rather than a sold panel.
Rabbits and hares also have big feet and powerful hind legs that enable them to leap to top speeds almost instantly even from a resting position.
And if you've ever watched rabbits eat, you may have noticed that its jaws move side to side. That's because their upper rows of teeth are spaced farther apart than the lower rows. This requires lateral jaw action to chew food.
In North America, lagomorphs include two species of unrabbit-like pikas that inhabit talus slopes in the high western mountains, 11 species of cottontails, and eight species of jackrabbits and hares. The most widely distributed species is the eastern cottontail. The "bunnies" we see in our backyards are invariably eastern cottontails.
Cottontails spend most of the day resting in a "form" -- a well-worn depression on the ground. It's usually nestled in a clump of dense grass in a thicket or under a brush pile. Contrary to popular belief, rabbits do not dig burrows. They occasionally seek refuge in an abandoned groundhog burrow to escape predators or harsh weather, but they spend most of their time above ground.
Cottontails began mating in February. Females give birth to their first litter after a pregnancy of 28 to 30 days. Prior to birthing, the female digs a shallow hole about the size of a clenched fist. She lines the nest with fur plucked from her belly and covers the hole with grass to camouflage it from above.