Mongolian gerbil

Mongolian gerbil
Wild gerbil in Mongolia
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Rodentia
Family: Muridae
Subfamily: Gerbillinae
Genus: Meriones
Subgenus: Pallasiomys
Species: M. unguiculatus
Binomial name
Meriones unguiculatus
(Milne-Edwards, 1867)
Meriones unguiculatus, Wilhelma Zoo, Stuttgart, Germany

Meriones unguiculatus, the Mongolian jird or Mongolian gerbil is a rodent belonging to subfamily Gerbillinae.[2] It is the most widely known species of the gerbil subfamily, and is the usual gerbil species to be kept as a pet or experimental animal, when it is known as the domesticated gerbil. Like the Syrian or golden hamster, it was first brought to the United States in 1954 by Dr. Victor Schwentker for use in research. Forty-four pairs were caught in Mongolia and brought to England. They were described as "squirrel colors... with long furry tails."[3] They are somewhat larger than mice, with a body about 12 cm long (and a tail of similar length), with body mass averaging 50-55 grams in females and 60 grams in males.[4]

The Mongolian gerbil is classed as a "prohibited new organism" under New Zealand's Hazardous Substances and New Organisms Act 1996, preventing it from being imported into the country.[5]

Origin

Meriones unguiculatus evolved on the semideserts and steppes of Mongolia. There, they developed long legs for jumping and running from predators, teeth to deal with hard seeds and plant matter, and water conservation techniques that allow them to survive in the arid climate, such as the ability to use dry food or stores of fat to generate metabolic water. Mongolian gerbils do not have many natural enemies due to the harsh climate. Most predators are birds of prey or snakes. Mongolian gerbils are diurnal, but return to their burrows for the coldest and hottest parts of the day.

Habitat

The species M. unguiculatus came originally from Mongolia. Its habitat there is mainly semideserts and steppes. Soil on the steppes is sandy and is covered with grasses, herbs, and shrubs. The steppes have cool, dry winters and hot summers. The temperature can get up to 50 °C (122 °F), but the average temperature for most of the year is around 20 °C (68 °F).

In the wild, these gerbils live in groups generally consisting of one parental pair, the most recent litter, and a few older pups. Only the dominant female will produce pups, but she will mate with multiple males while in estrus (heat). One group of gerbils generally ranges over 325–1,550 square metres (0.08–0.38 acres).

A group lives in a central burrow with 10–20 exits. Some deeper burrows with only one to three exits in their territory may exist. These deeper burrows are used to escape from predators when they are too far from the central burrow. A group's burrows often interconnect with other groups.

History

The first known mention of gerbils came in 1866, by Father Armand David, who sent "yellow rats" to the Museum of Natural History (Musée d'Histoire Naturelle) in Paris, from northern China. They were named Meriones unguiculatus by the scientist Milne-Edwards in 1867. This scientific name in a combination of Greek and modified Latin loosely translates as "clawed warrior" in English, partly stemming from the Greek warrior Meriones in Homer's Iliad, combined with 'unguiculate' meaning to have claws or nails.

Gerbils only became popular pets after 1954, when 20 breeding pairs were brought to the United States from eastern Mongolia for scientific testing. Almost all pet gerbils today are descended from these 40. Gerbils were brought to the United Kingdom in 1964 from the United States.

Gerbils In Science

The Mongolian gerbil has become an important research animal for several reasons. In the wild during the long, cold winter of the arid and semi-arid regions of Mongolia, China and Russia the gerbil stays in small social groups mostly underground in a series of burrows in which separate areas are designated for food storage, sleeping, and voiding. The enclosed living habitats of domestication is similar and gerbils easily adapted to the new setting. In addition gerbils are able to manufacture most vitamins in their metabolic system so fresh vs. dehydrated foods are not a requirement for their health, and indeed can give them diarrhea. The extra dry environment this produces in their living areas keeps the growth of bacteria and fungi down and keeps odours down too. This means they are very easy animals to keep in a research setting.

About 50% of Mongolian gerbils also display an epileptic faint when under stress which might serve as a way to play dead in the wild. This characteristic has proven very useful to researchers of epilepsy and related illnesses.

During meiosis male Mongolian gerbils do not interchange reciprocal alleles between pairs of homologous chromosomes ("chiasmata" or "Crossing Over"), a trait very rare in eutherian mammals and indeed animals in general. Meiotic recombination occurs in females alone.

While gerbils are intelligent and social animals, they have not performed as well as rats at intelligence tests based on a maze pattern because they prefer to explore a new environment thoroughly rather than go straight to the food reward. Their curiosity is apparently greater than their desire to eat.

Gerbils as Pets

Pet gerbils eating millet

The Mongolian gerbil, a gentle and hardy animal, has become a popular pet. It was first brought from China to Paris, France in the 19th century, and became a popular house pet.[6] It was then brought to the United States in 1954 by Dr. Victor Schwentker for use in research.[3] Selective breeding for the pet trade has resulted in a wide range of different color and pattern varieties.[7]

Mongolian gerbils prefer to live in pairs or groups rather than alone. They are social and gentle, and do not bite readily. As diggers and tunnel-makers they are better suited to a tank with a deep substrate rather than a hamster cage, since the absorbent substrate is liable to be kicked up and out of a cage pretty quickly. Gerbils are also chewers and need plenty of cardboard items and chew toys. Cardboard will be chewed up into bedding and mixed with the substrate. Gerbils do not need fresh food and indeed it can give them diarrhea, a diet based on a seed, millet and alfalfa pellet mix is sufficient. Water should be provided in a drip-feed system to prevent the accidental build-up of harmful molds in the tank environment. Although gerbils are desert-adapted, they do require water to be supplied at all times. Care should be taken not to introduce new smells suddenly into the tank, which is considered by the gerbils to be their territory. Gerbils are active and appreciate a running or exercise wheel. Repetitive corner digging can be minimized by providing tunnels while gerbils are in their formative months. As with most animals, they appreciate a secure, private area that is dark for sleeping.[8]

Major Colours

Currently recognized colour morphs and their genetic basis are described below.[9]

Golden Agouti
Lilac
Dove
Burmese
Light Colourpoint Agouti
Nutmeg
Silver Nutmeg
Schimmels
Mottled black

Note: Although some gerbil owners call some coat varieties "Fox," for example Yellow Fox, the fox gene is not in gerbils which is misleading.

Breeding

Though not much is known about breeding in wild Mongolian gerbils, we know that they can have as many as 18 pups, compared to pet gerbils which can only have 14. The families make sure all young females in their groups leave before that can fall pregnant and kill the mothers' newer pups whilst still in the family unit. The father or older brothers will mate with younger females. These young females have the ability to carry sperm for up to 2 weeks until they are sexually mature (at 3–4 months) so that they can make a family of their own without the interference of another male who may kill the fathers pups. This is why it isn't recommended to keep an older male gerbil with a younger female as a cage mate for a prolonged amount of time.

References

  1. N. Batsaikhan & K. Tsytsulina (2008). "Meriones unguiculatus". IUCN Red List of Threatened Species. Version 2011.2. International Union for Conservation of Nature. Retrieved January 26, 2012.
  2. Musser, G.G.; Carleton, M.D. (2005). "Superfamily Muroidea". In Wilson, D.E.; Reeder, D.M. Mammal Species of the World: A Taxonomic and Geographic Reference (3rd ed.). Johns Hopkins University Press. p. 1239. ISBN 978-0-8018-8221-0. OCLC 62265494.
  3. 1 2 Schwentker, V. "The Gerbil. A new laboratory animal." Ill Vet 6: 5–9, 1963.
  4. Chen, J. (2001-04-09). "Meriones unguiculatus: Mongolian jird". Animal Diversity Web. University of Michigan. Retrieved 2015-04-20.
  5. Hazardous Substances and New Organisms Act 2003 - Schedule 2 Prohibited new organisms, New Zealand Government, retrieved 26 January 2012
  6. "Gerbils". huisdiereninfo.nl.
  7. "Gerbil Color Strips - American Gerbil Society". agsgerbils.org.
  8. "Comfortable Quarters for Gerbils in Research Institutions - Eva Waiblinger, Animal Behavior, Zoological Institute, University of Zürich, Switzerland".
  9. "Introduction to gerbil colours". Prairie Clan Gerbils.

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