Every domestic rabbit, in about 80 varieties, descends from the European rabbit, Oryctolagus cuniculus. Because of people, European rabbits now live in the wild on every continent except Asia and Antarctica, although the last Ice Age had left them only in Iberia and nearby areas. A jackrabbit is not a rabbit but a hare, and hares live mostly in open country, but rabbits stay close to thick cover. In the hottest part of the day, a jackrabbit rests in the shade of a shrub or tall grass.

A frightened cottontail can run up to 18 miles per hour, and it often zigzags as it goes. A black-tailed jackrabbit, which is a hare, can spring 20 feet in one bound and reach 30 to 35 miles per hour on a zigzag course. That is much faster than a cottontail. The snowshoe hare, a close relative of rabbits, changes color with the seasons: its summer coat is rusty or grayish brown, and in winter its fur turns almost entirely white.

A rabbit has two pairs of upper front teeth, a big pair with a small peg tooth behind each, while a rodent has only one pair. A rabbit's front teeth never stop growing. They grow about 2 to 3 millimeters every week, which is why a pet rabbit needs hay: chewing it grinds the teeth down side to side. Carrots are only an occasional treat for a rabbit, not its main food.

A rabbit's eyes sit high on the sides of its head, so it can spot danger from almost any direction, and it has a blind spot under its chin and in front of its nose. A rabbit can move each of its big ears on its own to find where a sound is coming from, and a cottontail that senses danger may freeze in place or dash away. A rabbit may thump its back feet on the ground to warn of danger.

Some wild rabbits live in underground homes called warrens, and rabbits in a warren live in groups. A typical group has six to ten adults, and a big warren can hold up to 30 rabbits, and it can spread across two acres or more. A cottontail mother scrapes a shallow dip in the ground for her nest instead of digging a burrow. She lines her nest with grass and her own fur, and she stays away from it most of the day.

A baby rabbit is called a kit. Baby cottontails are born with no fur, and they cannot see. Young cottontails leave the nest when they are two to three weeks old, and they are on their own when they are about a month old. An eastern cottontail mother usually has two to four litters a year, and she can have another litter soon after she has had one. Most wild eastern cottontails live only two or three years.

A pet rabbit needs a lot of time and care. Pet rabbits eat mostly hay, and they should eat only a few pellets. Pet rabbits need other rabbits for company, and two pet rabbits should meet slowly, on neutral ground. A pet rabbit loose in a room must be kept safe from chewing electrical cords. A rabbit has a fragile backbone, so it must be held gently and kept from struggling. Never pick up a rabbit by its ears. A pet rabbit can live for 8 to 12 years.

Words to know

• domestic: kept by people
• hare: long-legged relative
• warrens: underground rabbit homes
• litters: groups of babies