Gerbil



A gerbil is 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 [1] (though some, including the common household pet, do exhibit crepuscular behavior), and almost all are omnivorous.

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

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 nineteenth century, and became a popular house pet.[2] It was then brought to the United States in 1954 by Dr. Victor Schwentker for use in research.[3]

Gerbils are typically between six and twelve inches (150 to 300 mm) long, including the tail which makes up approximately 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 approximately 2½ ounces.

Behavior
A young gerbil sitting by the food bowl to eatGerbils are social animals, and live in groups in the wild.[4] They rely on their sense of smell to identify other members of their clan. This is why it is important to use what is commonly referred to as the "split tank method" when introducing gerbils from separate litters. Gerbils are known to attack and often kill those carrying an unfamiliar scent.[5]

Gerbils as pets
Gerbils were first introduced to the pet industry in 1964. These were the Mongolia gerbils. Their value as pets was soon appreciated and they are now found in pet shops all over the UK and USA. Due to the threat they pose to indigenous ecosystems and existing agricultural operations, it is illegal to purchase, import, or keep a gerbil as a pet in the U.S. state of California.[6]

Housing in captivity
A common misunderstanding when purchasing a home for pet gerbils is that they can live in housing designed for hamsters and mice. This is not correct as they need to be able to dig tunnel systems, rather than have them created for them. The commonly plastic structure of hamster and mouse cages is inappropriate for gerbils due to their ability to gnaw through it very quickly. Plastic can cause serious health issues for the animal if ingested, therefore many owners refrain from having any plastic in the tank and rely entirely on wooden toys.[7] There is conflicting information from gerbil societies from throughout the globe with regards to tank sizing. However, a common minimum given appears to be 10 imperial gallons per gerbil.[8]

Mating
Gerbils will mate for several hours, in frequent short bursts followed by short chases where the female allows the male to catch her. Once he catches her, the female will squeak and make flick motions to get the male off her. Males will not attack females except in rare circumstances which may also include them having been separated from their original mates, or widowed. A female may attack a male, but usually he is more than a match for her.[9]

Teeth problems
Misalignment of incisors due to injury or malnutrition may result in overgrowth, which can cause injury to the roof of the mouth. Symptoms include a dropped or loss of appetite, drooling, weight loss, or foul breath.[12] 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 "run-about ball", which can cause broken limbs or a fractured spine (for which there is no cure).[12] [13]

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.[12]

Epilepsy
Between 20 percent and 50 percent of all pet gerbils have the seizure disorder epilepsy.[14] 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.[15] Another way to avoid a gerbil having a seizure is to refrain from blowing in the animals face (often used to "train" the pet not to bite), this is used in a lab environment to induce seizures for medical research.[16]

Tumors
Tumors, both benign and malignant, are fairly common in pet gerbils, and are most common in females over the age of 2. Usually, the tumors involve the ovaries, causing an extended abdomen, or the skin, with tumors most often developing around the ears, feet, mid-abdomen, and base of the tail, appearing as a lump or abscess.<sup class="reference" id="cite_ref-mi_14-1">[15] The scent gland (positioned on the abdomen) should be checked regularly, a veterinarian can operate on the lump where possible.<sup class="reference" id="cite_ref-16">[17]

Tail sloughing
Gerbils can lose their tails due to improper handling, being attacked by another animal, or getting their tail 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.<sup class="reference" id="cite_ref-mi_14-2">[15]

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.<sup class="reference" id="cite_ref-mi_14-3">[15]

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.<sup class="reference" id="cite_ref-17">[18]

Captive-bred gerbils
A Burmese colored gerbilA male and female fat-tailed gerbil (Pachyuromys duprasi)There are many color varieties of gerbil available in pet shops today, generally the result of years of selective breeding.

There are over 20 different coat colors in the Mongolian gerbil, which has been captive-bred the longest.<sup class="reference" id="cite_ref-18">[19]

Another species of gerbil has also been recently introduced to the pet industry: the Fat-tailed Gerbil, or duprasi. They’re smaller than the common Mongolian gerbils and have long soft coats and a short, fat tail, appearing more like a hamster. There is a variation on the normal duprasi coat which 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.<sup class="reference" id="cite_ref-gerbilinfo_19-0">[20] <sup class="reference" id="cite_ref-20">[21]

White spotting has been reported in not only the Mongolian Gerbil, but also the Pallid Gerbil<sup class="reference" id="cite_ref-21">[22] and possibly Sundervall's Jird.<sup class="reference" id="cite_ref-22">[23]

A long-haired mutation, a grey agouti or chinchilla mutation, white spotting, and possibly a dilute mutation have also appeared in Shaw's Jirds,<sup class="reference" id="cite_ref-23">[24] and white spotting and a dilute mutation have shown up in Bushy-tailed Jirds.<sup class="reference" id="cite_ref-24">[25]