Friday, February 19, 2010

Rabbit

From Wikipedia, the free encyclopedia

Jump to: navigation, search
Rabbit
Eastern Cottontail (Sylvilagus floridanus)
Scientific classification
Kingdom: Animalia
Superphylum: Chordata
Phylum: Vertebrata
Class: Mammalia
Order: Lagomorpha
Family: Leporidae
in part

Genera

Rabbits are small mammals in the family Leporidae of the order Lagomorpha, found in several parts of the world. 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). There are many other species of rabbit, and these, along with pikas and hares, make up the order Lagomorpha.

Contents

[hide]

Location and habitat

Entrance to a rabbit burrow
Entrance to a rabbit burrow with rabbit droppings near entrance

The rabbit lives in many areas around the world. Rabbits live in groups, and the best known species, the European rabbit lives in underground burrows, or rabbit holes. A group of burrows is called a warren. [1] Meadows, woods, forests, thickets, and grasslands are areas in which rabbits live.[1] They also inhabit deserts and wetlands. More than half the world's rabbit population resides in North America.[1] They also live in Europe, India, Sumatra, Japan, and parts of Africa. The European rabbit has been introduced to many places around the world.[2]

Characteristics and anatomy

The rabbit's long ears, which can be more than 10 cm (4 in) long, are probably an adaptation for detecting predators. They have large, powerful hind legs. Each foot has five toes, with one greatly reduced in size. They are digitigrade animals; they move around on the tips of their toes. Wild rabbits do not differ much in their body proportions or stance, with full, egg-shaped bodies. Their size can range anywhere from 20 cm (8 in) in length and 0.4 kg in weight to 50 cm (20 in) and more than 2 kg. The fur is most commonly long and soft, with colors such as shades of brown, gray, and buff. The tail is a little plume of brownish fur (white on top for cottontails).[2]

Cecal pellets

Rabbits are hindgut digesters. This means that most of their digestion takes place in their large intestine and cecum. In rabbits, the cecum is about 10 times bigger than the stomach, and it, along with the large intestine, makes up roughly 40% of the rabbit's digestive tract.[3] Cecotropes, sometimes called "night feces", come from the cecum and are high in minerals, vitamins and proteins that are necessary to the rabbit's health. Rabbits eat these to meet their nutritional requirements. This process allows rabbits to extract the necessary nutrients from their food.[4]

Rabbits have two sets of incisor teeth, one behind the other. This way they can be distinguished from rodents, with which they are often mistaken.[5]

Behavior

A rabbit's side view

Rabbits, being prey animals, tend to be exploratory in new spaces and when confronted with a threat, they tend to freeze and observe. Rabbit vision has a remarkably wide field of vision, and a good deal of it is devoted to overhead scanning. Even indoors, rabbits will scan for overhead threats.

Rabbits have a complex social structure, and like dogs, will attempt to establish a hierarchy and dominance.

Reproduction

Domestic pet kittens 1 hour after birth.

Female rabbits do not actually ovulate until after breeding. They have a bifurcated uterus and often, breeding can involve multiple acts that can result in multiple impregnations from different bucks (male rabbits). Males are commonly sterile during the heat of summer months.

A litter of rabbit kits (baby rabbits) can be as small as a single kit, ranging up to 12 or 13; however there have been litters as big as 18. The gestation period is 30–32 days.[6]

Nest with young.

Diet and eating habits

Rabbits are herbivores who feed by grazing on grass, forbs, and leafy weeds. In consequence, 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) to digest their food further and extract sufficient nutrients.[7]

Rabbits graze heavily and rapidly for roughly the first half hour of a grazing period (usually in the late afternoon), followed by about half an hour of more selective feeding. In this time, the rabbit will also excrete many hard fecal pellets, being waste pellets that will not be reingested. If the environment is relatively non-threatening, the rabbit will remain outdoors for many hours, grazing at intervals. While out of the burrow, the rabbit will occasionally reingest its soft, partially digested pellets; this is rarely observed, since the pellets are reingested as they are produced. Reingestion is most common within the burrow between 8 o'clock in the morning and 5 o'clock in the evening, being carried out intermittently within that period.

Hard pellets are made up of hay-like fragments of plant cuticle and stalk, being the final waste product after redigestion of soft pellets. These are only released outside the burrow and are not reingested. Soft pellets are usually produced several hours after grazing, after the hard pellets have all been excreted. They are made up of micro-organisms and undigested plant cell walls.

The chewed plant material collects in the large cecum, a secondary chamber between the large and small intestine containing large quantities of symbiotic bacteria that help with the digestion of cellulose and also produce certain B vitamins. The pellets are about 56% bacteria by dry weight, largely accounting for the pellets being 24.4% protein on average. These pellets remain intact for up to six hours in the stomach; the bacteria within continue to digest the plant carbohydrates. The soft feces form here and contain up to five times the vitamins of hard feces. After being excreted, they are eaten whole by the rabbit and redigested in a special part of the stomach. This double-digestion process enables rabbits to use nutrients that they may have missed during the first passage through the gut, and thus ensures that maximum nutrition is derived from the food they eat.[2] This process serves the same purpose within the rabbit as rumination does in cattle and sheep.[8]

Rabbits are incapable of vomiting due to the physiology of their digestive system.[9]

Diseases

Differences from hares

Rabbits are clearly distinguished from hares in that rabbits are altricial, having young that are born blind and hairless. In contrast, hares are generally born with hair and are able to see (precocial). All rabbits except the cottontail rabbit live underground in burrows or warrens, while hares live in simple nests above the ground (as does the cottontail rabbit), and usually do not live in groups. Hares are generally larger than rabbits, with longer ears, and have black markings on their fur. Hares have not been domesticated, while European rabbits are often kept as house pets. In gardens, they are typically kept in hutches — small, wooden, house-like boxes — that protect the rabbits from the environment and predators.

As pets

Oryctolagus cuniculus

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. Animal welfare organisations such as the House Rabbit Society recommend that rabbits do not make good pets for small children because children generally 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 7 years old and older usually have the maturity required to care for a rabbit.[10]

As food and clothing

An Australian 'Rabbiter' circa 1900
A load of rabbit skins, Northern Tablelands, New South Wales
Rabbits may be slaughtered commercially for their meat.

Leporids such as European rabbits and hares are a food meat in Europe, South America, North America, some parts of the Middle East, and China, among other places.

Rabbit is still commonly sold in UK butchers and markets, although not frequently in supermarkets. At farmers markets and the famous Borough Market in London, rabbits will be displayed dead and hanging unbutchered in the traditional style next to braces of pheasant and other small game. Rabbit meat was once commonly sold in Sydney, Australia, the sellers of which giving the name to the rugby league team the South Sydney Rabbitohs, but quickly became unpopular after the disease myxomatosis was introduced in an attempt to wipe out the feral rabbit population (see also Rabbits in Australia).

When used for food, rabbits are both hunted and bred for meat. Snares or guns along with dogs are usually employed when catching wild rabbits for food. In many regions, rabbits are also bred for meat, a practice called cuniculture. Rabbits can then be killed by hitting the back of their heads, a practice from which the term rabbit punch is derived. Rabbit meat is a source of high quality protein.[11] It can be used in most ways chicken meat is used. In fact, well-known chef Mark Bittman says that domesticated rabbit tastes like chicken because both are blank palettes upon which any desired flavors can be layered.[12] Rabbit meat is leaner than beef, pork, and chicken meat. Rabbit products are generally labeled in three ways, the first being Fryer. This is a young rabbit between 4.5 and 5 pounds and up to 9 weeks in age.[13] This type of meat is tender and fine grained. The next product is a Roaster; they are usually over 5 pounds and up to 8 months in age. The flesh is firm and coarse grained and less tender than a fryer. Then there are giblets which include the liver and heart. One of the most common types of rabbit to be bred for meat is New Zealand white rabbit.

There are several health issues associated with the use of rabbits for meat, one of which is Tularemia or Rabbit Fever.[14] Another is so-called rabbit starvation, due most likely to essential fatty acid deficiencies in rabbit meat and synthesis limitations in human beings.

Rabbits are a favorite food item of large pythons, such as Burmese pythons and reticulated pythons, both in the wild, as well as pet pythons. A typical diet for example, for a pet Burmese python, is a rabbit once a week.[citation needed]

Rabbit pelts are sometimes used for clothing and accessories, such as scarves or hats. Angora rabbits are bread for their long, fine hair, which can be sheared and harvested like sheep wool. Rabbits are very good producers of manure; additionally, their urine, being high in nitrogen, makes lemon trees very productive. Their milk may also be of great medicinal or nutritional benefit due to its high protein content.[citation needed]

Environmental problems

When introduced to a new area, rabbits can quickly overpopulate and become a nuisance, as they have on this university campus.

Rabbits have been a source of environmental problems when introduced into the wild by humans. As a result of their appetites, and the rate at which they breed, wild rabbit depredation can be problematic for agriculture. Gassing, barriers (fences), shooting, snaring, and ferreting have been used to control rabbit populations, but the most effective measures are diseases such as myxomatosis (myxo or mixi, colloquially) and calicivirus. In Europe, where rabbits are farmed on a large scale, they are protected against myxomatosis and calicivirus with a genetically modified virus. The virus was developed in Spain, and is beneficial to rabbit farmers. If it were to make its way into wild populations in areas such as Australia, it could create a population boom, as those diseases are the most serious threats to rabbit survival. Rabbits in Australia are considered to be such a pest that land owners are legally obliged to control them.[citation needed]

In culture and literature

Rabbit and Acorn Jay Birds, a Song Dynasty era painting by Chinese artist Cui Bai, painted in 1061 AD.

Rabbits are often used as a symbol of fertility or rebirth, and have long been associated with spring and Easter as the Easter Bunny. The species' role as a prey animal also lends itself as a symbol of innocence, another Easter connotation.

Additionally, rabbits are often used as symbols of playful sexuality, which also relates to the human perception of innocence, as well as its reputation as a prolific breeder.

Folklore and mythology

The rabbit often appears in folklore as the trickster archetype, as he uses his cunning to outwit his enemies.

On the Isle of Portland in Dorset, UK, the rabbit is said to be unlucky and speaking its name can cause upset with older residents. This is thought to date back to early times in the quarrying industry, where piles of extracted stone (not fit for sale) were built into tall rough walls (to save space) directly behind the working quarry face; the rabbit's natural tendency to burrow would weaken these "walls" and cause collapse, often resulting in injuries or even death. The name rabbit is often substituted with words such as “long ears” or “underground mutton”, so as not to have to say the actual word and bring bad luck to oneself. It is said that a public house (on the island) can be cleared of people by calling out the word rabbit and while this was very true in the past, it has gradually become more fable than fact over the past 50 years.

Other fictional rabbits

The rabbit as trickster appears in American popular culture; for example the Br'er Rabbit character from African-American folktales and Disney animation; and the Warner Bros. cartoon character Bugs Bunny.

Anthropomorphized rabbits have appeared in a host of works of film, literature, and technology, notably the White Rabbit and the March Hare in Lewis Carroll's Alice's Adventures in Wonderland; in the popular novels Watership Down, by Richard Adams (which has also been made into a movie) and Rabbit Hill by Robert Lawson, as well as in Beatrix Potter's Peter Rabbit stories.

Urban legends

It was commonly believed that pregnancy tests were based on the idea that a rabbit would die if injected with a pregnant woman's urine. This is not true. However, in the 1920s it was discovered that if the urine contained the hCG, a hormone found in the bodies of pregnant women, the rabbit would display ovarian changes. The rabbit would then be killed to have its ovaries inspected, but the death of the rabbit was not the indicator of the results. Later revisions of the test allowed technicians to inspect the ovaries without killing the animal. A similar test involved injecting Xenopus frogs to make them lay eggs, but animal tests for pregnancy have been made obsolete by faster, cheaper, and simpler modern methods.

Classifications

Rabbits and hares were formerly classified in the order Rodentia (rodent) until 1912, when they were moved into a new order Lagomorpha. This order also includes pikas.

Order Lagomorpha

No comments:

Post a Comment