Rabbits are mammals which belong to the Lagomorph order that also includes hares and pikas (Lagomorph means 'hare-shaped'), under which there are over 50 species. There are seven different genera in the family classified as rabbits, including the European rabbit (Oryctolagus cuniculus), Cottontail rabbit (genus Sylvilagus; 13 species), and the Amami rabbit (Pentalagus furnessi, endangered species on Amami Ōshima, Japan). They are similar to rodents in that they have incisor teeth that continually grow. The domestic rabbit is derived from any of the varieties of wild European rabbit. The domestic species most widely kept are Oryctolagus cuniculus which has been bred over the years to develop many different breeds of rabbit through selective breeding.
Rabbits are naturally herbivores who feed by grazing on grass, forbs, and leafy weeds. In addition, their diet contains large amounts of cellulose, which is hard to digest. Rabbits solve this problem by passing two distinct types of feces: hard droppings and soft black viscous pellets, the latter of which are immediately eaten. Rabbits reingest their own droppings (rather than chewing the cud as do cows and many other herbivores) in order to fully digest their food and extract sufficient nutrients. Domestic rabbits have adapted to the many scientifically produced ready mixes available.
The long ears of rabbits are most likely an adaptation for detecting predators. In addition to their prominent ears, rabbits have long, powerful hind legs and a short tail. Each foot has five digits (one reduced); rabbits move about on the tips of the digits in a fashion known as digitigrade locomotion.
Most rabbits produce many offspring each year, although scarcity of resources may cause this potential to be suppressed. A combination of factors allows the high rates of reproduction commonly associated with rabbits. Rabbits generally are able to breed at a young age, and many regularly conceive litters of up to seven young, often doing so four or five times a year due to the fact that a rabbit's gestation period is only 28 to 31 days. In addition, females exhibit induced ovulation, their ovaries releasing eggs in response to copulation rather than according to a regular cycle. They can also undergo postpartum estrus, conceiving immediately after a litter has been born.
Newborn rabbits are naked, blind, and helpless at birth. Mothers are remarkably inattentive to their young and are almost absentee parents, commonly nursing their young only once per day and for just a few minutes. To overcome this lack of attention, the milk of rabbits is highly nutritious and among the richest of that of all mammals. The young grow rapidly, and most are weaned in about a month. Males (bucks) do not assist in rearing the kittens.
Pet rabbits kept indoors are referred to as house rabbits. House rabbits typically have an indoor pen or cage and a rabbit-safe place to run and exercise, such as an exercise pen, living room or family room. Rabbits can be trained to use a litter box and some can learn to come when called. Domestic rabbits that do not live indoors can also often serve as companions for their owners, typically living in an easily accessible hutch outside the home. Some pet rabbits live in outside hutches during the day for the benefit of fresh air and natural daylight and are brought inside at night.
Whether indoor or outdoor, pet rabbits' pens are often equipped with enrichment activities such as shelves, tunnels, balls, and other toys. Pet rabbits are often provided additional space in which to get exercise, simulating the open space a rabbit would traverse in the wild. Exercise pens or lawn pens are often used to provide a safe place for rabbits to run.
A pet rabbit's diet typically consists of unlimited Timothy hay, a small amount of pellets, and a small portion of fresh vegetables.
Rabbits are social animals. Rabbits as pets can find their companionship with a variety of creatures, including humans, other rabbits, guinea pigs, and sometimes even cats and dogs. Rabbits do not make a good pets for small children because they do not know how to stay quiet, calm, and gentle around rabbits. As prey animals, rabbits are alert, timid creatures that startle easily. They have fragile bones, especially in their backs, that require support on the belly and bottom when picked up. Children 10 years old and older usually have the maturity required to care for a rabbit.