Gerbil

Gerbil Fossil range: Late Miocene - Recent
Scientific classification
Kingdom: Animalia Phylum: Chordata Class: Mammalia Order: Rodentia Superfamily: Muroidea Family: Muridae Subfamily: Gerbillinae Gray, 1825
Genera
Ammodillus Brachiones Desmodilliscus Desmodillus Dipodillus Gerbilliscus Gerbillurus Gerbillus Meriones Microdillus Pachyuromys Psammomys Rhombomys Sekeetamys Tatera Taterillus

Gerbil is the common name for any of the small to medium-sized rodents in the Old World Muridae subfamily Gerbillinae, characterized by a mouse-like appearance, generally long tails and long, narrow hind feet, long claws, very thin enamel on the incisors, and 12 thoracic and 7 lumbar vertebrae. These terrestrial mammals, once known simply as desert rats, are adapted to arid conditions and are distributed throughout Africa, the Middle East, and central Asia, largely in dry habitats, including deserts. Some in this subfamily are also called by the common name of jird. There are over 100 species in 16 genera of gerbillines. As murids, gerbils are in the same family as true rats and mice.

In the wild, gerbils provide many values for the ecosystem. In food chains, gerbils consume nuts, seeds, fruits, grasses, insects, and bird eggs and are preyed upon by snakes, birds of prey such as owls, and other carnivores. They also can play a role as pollinators of certain plants and likely in seed dispersal. Gerbillines, and in particular Meriones unguiculatus, the Mongolian gerbil, also provide a particular value to humans as a popular house pet and experimental animal, used for medical, psychological, and physiological research.

Overview and physical description

As rodents (order Rodentia), gerbils are characterized by dentition specialized for gnawing, with a single pair of upper incisors and single pair of lower incisors that grow continuously throughout their life and must be worn down by gnawing. The incisors have enamel on the outside and exposed dentine on the inside, so they self-sharpen during gnawing. Rodents lack canines and first premolars, which creates a space between their incisors and their grinding teeth (molars).

Within Rodentia, the gerbils belong to the superfamily Muroidea a vary large taxon that also includes hamsters, voles, true mice and rats, and many other relatives. They are the most populous group of rodents in the Northern Hemisphere and occupy a vast variety of habitats on every continent except Antarctica. They are often found in fossil occlusions of bones cached by past predators such as owls and other birds of prey.

Gerbls, along with true mice and rats, spiny mice, and the crested rat belong to the family Muridae. Murids are the largest family of mammals, containing over 700 species. Murids typically have slender bodies with scaled tails, and pointed snouts with prominent whiskers, but there is wide variation in these broad traits. The dental formula of murids is ${\tfrac {1.0.0.1-3}{1.0.0.1-3}}$.

Gerbils comprise the murid subfamily Gerbillinae. Gerbillines have 12 thoracic and 7 lumbar vertebrae and have very thin layers of enamel on the incisors compared to the other murids. The dental formula of gerbillines is ${\tfrac {1.0.0.3}{1.0.0.3}}$ = 16, with the ecceptoin of the genus Desmodilliscus, whose members only have two lower molars on each side. (Poor 2005).

Gerbils are small to medium-sized rodents, generally slender, and with tails longer than their body. The body length of gerbils ranges from 50 to 200 millimeters, while the tail lengths range from 56 to 245 millimeters. Weights may range from 10 grams to 227 grams. They tend to have long, narrow hind feet and long claws. Ears may be long or short and fur also may be long or short, with the color of the pelage varying widely, including such colors as reddish, gray, olive, yellowish, dark brown, orangish and so forth (Poor 2005).

The word "gerbil" is a diminutive form of "jerboa", though the jerboas are an unrelated group of rodents occupying a similar ecological niche.

Distribution

These terrestrial mammals, once known simply as desert rats, are adapted to arid conditions and are distributed throughout Africa, the Middle East, and central Asia, largely in dry habitats, including deserts. Some in this subfamily are also called by the common name of jird. There are over 100 species in 16 genera of gerbillines. As murids, gerbils are in the same family as true rats and mice.

a small mammal of the order Rodentia. Once known simply as "desert rats", the gerbil subfamily includes about 110 species of African, Indian, and Asian rodents, including sand rats and jirds, all of which are adapted to arid habitats. Most are primarily diurnal (though some, including the common household pet, do exhibit crepuscular behavior), and almost all are omnivorous.

One Mongolian species, Meriones unguiculatus, also known as the clawed jird, is a gentle and hardy animal that has become a popular pet. It was first brought from China to Paris, France in the 19th century, and became a popular house pet. It was then brought to the United States in 1954 by Dr. Victor Schwentker for use in research.

Gerbils are typically between six and 12 inches (150 and 300 mm) long, including the tail, which makes up about one-half of their total length. One species, the great gerbil, or Rhombomys opimus, originally native to Turkmenistan, can grow to more than 16 inches (400 mm). The average adult gerbil weighs about 2.5 oz. (70 g).]</ref> The teeth must be clipped by a veterinarian regularly for as long as required.

Trauma

Common injuries are caused by gerbils being dropped or falling, often while inside of a hamster ball, which can cause broken limbs or a fractured spine (for which there is no cure).

Neglect

A common problem for all small rodents is neglect, which can cause the gerbils to not receive adequate food and water, causing serious health concerns, including dehydration, starvation, stomach ulcers, eating of bedding material, and cannibalism.

Epilepsy

Between 20 and 50% of all pet gerbils have the seizure disorder epilepsy. The seizures are thought to be caused by fright, handling, or a new environment. The attacks can be mild to severe, but do not typically appear to have any long-term effects, except for rare cases where death results from very severe seizures. A way to avoid a gerbil having a seizure is to refrain from blowing in the animal's face (often used to "train" the pet not to bite), this is used in a lab environment to induce seizures for medical research.

Tumors

Tumors, both benign and malignant, are fairly common in pet gerbils, and are most common in females over the age of two. Usually, the tumors involve the ovaries, causing an extended abdomen, or the skin, with tumors most often developing around the ears, feet, midabdomen, and base of the tail, appearing as a lump or abscess. The scent gland (positioned on the abdomen) should be checked regularly; a veterinarian can operate on the lump where possible.

Tail sloughing

Gerbils can lose their tails due to improper handling, being attacked by another animal, or getting their tails stuck. The first sign is a loss of fur from the tip of the tail, then, the skinless tail dies off and sloughs, with the stump usually healing without complications.

Tyzzer's disease

The most common infectious disease in gerbils is Tyzzer's disease, which is often caused by either stress or bacteria, and produces symptoms such as ruffled fur, lethargy, hunched posture, poor appetite, diarrhoea, and often death. It quickly spreads between gerbils in close contact.

Deafness and inner ear problems

A problem with the inner ear can be spotted by a gerbil leaning to one side quite obviously. The fluids in the ears affect balance. However, this does not appear to affect the gerbils too much, which have an aptitude of just getting on with things, and getting used to their conditions. Gerbils with "extreme white spotting" colouring are susceptible to deafness; this is thought to be due to the lack of pigmentation in and around the ear.

Captive-bred gerbils

File:Burmese colored gerbil.jpg

A Burmese colored gerbil

A male and female fat-tailed gerbil (Pachyuromys duprasi)

Many color varieties of gerbils are available in pet shops today, generally the result of years of selective breeding.

Over 20 different coat colors occur in the Mongolian gerbil, which has been captive-bred the longest.

Another species of gerbil has also been recently introduced to the pet industry: the fat-tailed gerbil, or duprasi. They are smaller than the common Mongolian gerbils, and have long, soft coats and short, fat tails, appearing more like a hamster. The variation on the normal duprasi coat is more gray in color, which may be a mutation, or it may be the result of hybrids between the Egyptian and Algerian subspecies of duprasi.

White spotting has been reported in not only the Mongolian gerbil, but also the pallid gerbil and possibly Sundervall's Jird.

A long-haired mutation, a grey agouti or chinchilla mutation, white spotting, and possibly a dilute mutation have also appeared in Shaw's jirds, and white spotting and a dilute mutation have shown up in Bushy-tailed Jirds.

See also

• Jird
• Jerboa
• Indian desert jird

References

ISBN links support NWE through referral fees

Resources

• McKenna, M. C. and S. K. Bell. 1997. Classification of Mammals above the Species Level. Columbia University Press, New York.
• Musser, G. G. and M. D. Carleton. 1993. Family Muridae. Pp. 501–755 in Mammal Species of the World a Taxonomic and Geographic Reference. D. E. Wilson and D. M. Reeder eds. Smithsonian Institution Press, Washington D.C.
• Nowak, R. M. 1999. Walker's Mammals of the World, Vol. 2. Johns Hopkins University Press, London.
• Pavlinov, I. Ya., Yu. A. Dubrovskiy, O. L. Rossolimo, E. G. Potapova. 1990. Gerbils of the world. Nauka, Moscow.
• http://www.research.usf.edu/cm/CMDC/C111_Normative_Biology_Diseases_Gerbils_7_03.pdf

Poor, A. 2005. "Gerbillinae" (On-line), Animal Diversity Web. Accessed October 27, 2013 at http://animaldiversity.ummz.umich.edu/accounts/Gerbillinae/

External links

• The UK's National Gerbil Society
• The Gerbils.com - Everything about the gerbil
• eGerbil- For everything gerbil!
• American Gerbil Society

Template:Muridae Template:Gerbillinae

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