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Meriones unguiculatus, the Mongolian jird or Mongolian gerbil is a rodent belonging to subfamily Gerbillinae. 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."
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.
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.
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 as pets
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. It was then brought to the United States in 1954 by Dr. Victor Schwentker for use in research. Selective breeding for the pet trade has resulted in a wide range of different color and pattern varieties.
- Golden Agouti — All Mongolian Gerbils in the wild are Golden Agouti, also called Agouti. The hair shafts on the back are grey at the base, gold in the middle and tipped with black, making an even mix of golden brown with black ticking. The belly is creamy white. An Agouti gerbil has black eyes.
- Black — A Black gerbil is black both on its back and on its belly. It most often has a "bib" or white line running down its chin. It also may have some white on its paws. A Black gerbil has black eyes.Black gerbils are also known to have a white belly.
- Argente — An Argente gerbil is orange with a white belly. It has deep ruby eyes. If one were to brush back the fur on its back, one would see that the roots are grey.
- Argente Cream — An Argente Cream gerbil is an Argente lightened by a Himalayan gene, c(h). It is light orange with a white belly and ruby eyes. The undercoat is grey like the Argente Gold, but diluted due to the c(h).
- Argente Fawn / Topaz — A Topaz gerbil is an Argente lightened by a gene called Chinchilla Medium, c(chm), formerly called Burmese, c(b). This color is lighter than an Argente Golden but darker than an Argente Cream, and it often has slightly darker points at the ears, nose and tail. It has ruby eyes. The undercoat is grey, but diluted due to the c(chm).
- Lilac — A Lilac gerbil is dark grey all over. It has ruby eyes.
- Dove — A Dove gerbil is a Lilac lightened by the Himalayan gene, c(h). It is a powdery light grey all over. It has ruby eyes.
- Sapphire — A Sapphire gerbil is a Lilac lightened by a gene called Chinchilla Medium, c(chm). This color is lighter than a Lilac but darker than a Dove. It has ruby eyes.
- Pink-eyed White — A Pink-eyed White gerbil is completely white with light ruby eyes.
- Burmese / Colourpoint Black — A Colourpoint black gerbil is an all over chocolate color. Around eight weeks or so, it will begin to develop darker points on the tail, nose, feet and tips of the ear. Often has a "bib" or white line running down the chin. It also may have some white on its paws. All Burmese gerbils have black eyes.
- Siamese / Light Colourpoint Black — A Siamese gerbil starts out a light mushroom color. Around eight weeks, it molts and the tail, nose, feet and tips of the ear go black. The main body color stays the same. A Siamese has black eyes. It also often has a "bib" or white line running down the chin. May also have some white on the paws.Younger Siamese gerbils can have lighter bands on their feet, but will fade on the back but may stay on the front. Their color is also described as "Mushroom colorpoint".
- Colorpoint Agouti — A Colorpoint Agouti has an off-white to grey base with a liberal amount of silvery-brownish ticking along the back. The belly is white and the eyes are black.
- Light Colorpoint Agouti — A Light Colorpoint Agouti has an off-white base with silvery-brownish ticking along the back. Its belly is white and its eyes are black.
- Grey Agouti — The hairs on the back of a Grey Agouti are dark grey with white in the middle, making an even salt-and-pepper look. They often have gold intermingled into the coat. The belly is white. Grey Agoutis have black eyes.
- Slate — A Slate gerbil is a greyish black color. Often has a "bib" or white line running down the chin. It may also have some white on the paws. A Slate has black eyes with a reddish reflective shine in bright light or flash, however this can also appear on Black gerbils with certain recessives i.e. c(chm).
- Ivory Cream — An Ivory Cream gerbil is creamy colored on its back with a light cream belly. It has ruby eyes.
- Ruby-Eyed White — A Ruby-Eyed White gerbil is white all over. It has ruby eyes. Also known as Red Eyed White.
- Dark Eyed Honey — A Dark Eyed Honey gerbil starts out with a bright orange back with a white belly and flanks. At 8 weeks it molts and a small amount of black ticking appears along its back. A Dark Eyed Honey has black eyes.
- Nutmeg — A Nutmeg gerbil starts out with a bright orange color over its entire body. At 8 weeks it molts and liberal black ticking appears along the back with a lesser amount on the belly, changing the color from an orangey-brown to almost pure black, depending on the extensiveness of the ticking. A Nutmeg gerbil has black eyes.
- Silver Nutmeg — A Silver Nutmeg gerbil's first coat is an ivory color. At 8 weeks the gerbil molts and the liberal greyish ticking appears along the back with a lesser amount on the belly. A Silver Nutmeg gerbil has black eyes.
- Red Eyed Honey / Yellow Fox — A Yellow Fox gerbil has a bright orange back with a white belly and flanks. It has ruby eyes.
- Saffron / Red Fox — A Red Fox is a bright orange color over its entire body, with the color lightening somewhat through the belly area. Often there is a "bib" or white line running down the chin. There may also be some white on the paws. A Red Fox has ruby eyes.
- Polar Fox — A Polar Fox starts out a creamy ivory color. At 8 weeks the gerbil molts and minimal greyish ticking appears along the back. The nails are clear. A Polar Fox has black eyes.
- Schimmel — A Schimmel gerbil starts out as an orange color. At eight weeks old it molts and the coat begins to lighten to a creamy white. The gerbil's body continues to lighten throughout its life until it can be left with a white body, while the tail, nose, feet and tips of the ears retain the orange. Schimmel gerbils have black eyes. A schimmel with ruby eyes is a Ruby Eyed Schimmel.
- Black Eyed White — A Black Eyed White gerbil is completely white with black eyes. Some have greyish ear tips and dark claws.
- Spotting - Dominant spotting can be in any coat variety and will lighten the fur around it. How the spotting will look depends on modifiers.
- Collared - A thick, unbroken band of spotting around the neck connecting to the white belly.
- Collar and blaze - A thick, unbroken band of spotting around the neck connecting to the white belly and an unbroken white blaze connecting the three spotting areas (neck, forehead and nose).
- Pied - The base coat color may be of any standard type except for white. There is a thick band of white around the neck and shoulder area to form a collar that is connected to a blazed down the forehead and face. The distinguishing feature are small spots on the rump and back area around the spinal area. These spots usually do not have clear edges. The gerbil may be 50% white before it is considered a mottled gerbil as long as the spotting pattern conforms to the standard, accepted pattern.
- Mottled - The coat color of the gerbil may be any standard coat color broken by small white patches accompanying a collar and blaze. The gerbil may be up to 75% white until it would be considered a variegated gerbil.
- Variegated - The variegated pattern is when any standard coat color is broken up by small white patches along with a collar and blaze. The difference between the variegated spotting form and the mottled spotting form is the amount of white. The variegated spotting is an extended form of mottling. There is more white on the back and rump, allowing less color to show through. This can form a 'dalmatian' pattern. Often the tail tuft and the end of the tail is white or lacking pigment.
- Extreme White - The extreme white pattern is associated with any standard color except for white. Here the coat color is 90% white and barely any of the base coat color, or any pigment, is remaining. There have been health concerns circulating about extreme white gerbils. Head tilts, lack of good balance, and repetitive running and circling has been reported in these gerbils. It has been found that these health concerns mostly affect gerbils with unpigmented (light pink/not very opaque) ears.
There are other spotting "types". Any that don't conform to show standards are usually classed as patched.
Note: Although some US gerbil owners call some coat varieties "fox" i.e. yellow fox, the fox gene is not in gerbils and this is therefore incorrect.
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.
- 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.
- Schwentker, V. "The Gerbil. A new laboratory animal." Ill Vet 6: 5–9, 1963.
- Hazardous Substances and New Organisms Act 2003 - Schedule 2 Prohibited new organisms, New Zealand Government, retrieved 26 January 2012
- Schwentker, V. "The Gerbil. A new laboratory animal." Ill Vet 6: 5–9, 1963.
- American Gerbil Society Color Strips