Fat-tailed gerbil
The fat-tailed gerbil ("Pachyuromys duprasi"), also called the duprasi gerbil or doop, is a rodent belonging to subfamily Gerbillinae. It is the only member of the genus Pachyuromys. These rodents are the most docile species of the gerbil subfamily. They have fluffy and soft fur. Fat-tailed gerbils have been available on the pet market for decades, but in the 21st century breeders can be hard to find. They are sometimes considered as pocket pets. Other common English names are: fat-tailed jird, fat-tailed rat, and beer mat gerbil. Names in other languages are: (أبو  ليه) in Egyptian Arabic, and (عضل أليان) in Standard Arabic, ' (French), ' (German), ' (Danish), ' (Finnish), and "" (Dutch). Description. The fat-tailed gerbil is a medium-sized gerbil. Its body length is about 10 cm (4"), with a tail length of about 5 cm (2"). This gerbil has a thick, soft, fluffy coat. The hair at the back and the head is yellow-coloured, with a dark grey basis and a small black tip. The belly is clear white. Fat-tailed gerbils weigh between 40 to 120 grams. Their body is round and somewhat flattened. They have no clear neck and a  very sharp face, with large oval-shaped black eyes. The ears of this species are low positioned, which gives this species a fox-like head. The legs are comparatively short for a gerbil. They look similar to a dwarf hamster, but unlike a hamster they have a pointed snout and a fat, almost bald, club-shaped tail from which they get their common name of 'fat-tailed gerbil'. The fat-tailed gerbil stores fat in its tail, in the same way that the camel stores fat in its hump. Therefore, a healthy fat-tailed gerbil should have a nicely rounded  tail. It is this tail which makes them easy to distinguish from all other gerbil species. Lifespan. Captive specimens of the fat-tailed gerbil have an average life span of between 2 and 4 years - although as many as 7 has been suggested in some reports such as https://animaldiversity.org/accounts/Pachyuromys_duprasi/. In the wild, they are unlikely to reach this age. Origin. The French zoologist Fernand Lataste discovered "Pachyuromys duprasi" in 1880 in Laghouat, Algeria. He was the first to describe the animal in detail in Le Naturaliste. Fat-tailed gerbils are originally found in the Northern Sahara (North-western Egypt, Libya , Tunisia, and Algeria). There they live in sparsely vegetated sand sheets or rocky deserts. In the wild, fat-tailed gerbils live in simple burrows about one meter deep, in hard sandy soil. They may also occupy other species' burrows. Food. Fat-tailed gerbils are, as their pointed snout would suggest, mostly insectivorous in the wild, but will eat also a variety of plants. In captivity, they are kept on normal basic rodent mix, used to feed Mongolian gerbils or hamsters. They are particularly fond of mealworms, crickets, moths, and almost any other insect, even beetles. They can also be given  some vegetables and fruit, like carrots, cauliflower, chicory, and apples. Because fat-tailed gerbils originated in dry areas and are not used to food which has high moisture content, they can get diarrhea after eating too much fruit and vegetable matter. Branches and twigs are rich in vitamins and very suitable besides their basic food, especially in winter. It is also good for their teeth, because they keep growing their whole life and by gnawing they keep their incisors at the right length. Hay is also very good for fat-tailed gerbils, because of its high fibre content. Housing. The  best way to keep fat-tailed gerbils is in a tank (aquarium or terrarium). It should measure at least for one or two gerbils. Fat-tailed gerbils are fond of digging, so it is important to provide them with a thick layer of bedding. Wood shavings can be used, but not fresh pine (kiln-dried pine is regularly used in the UK) or red cedar wood shavings; many rodents react to them and develop respiratory problems. Aspen wood shavings are also popular - as are cardboard-based substrates. They also benefit from taking a sand bath regularly to help prevent their  fur from appearing greasy although some keep their greasy appearance whatever. Fat-tailed gerbils will make a nest; this may be underground in their burrow, on the surface in the substrate, or in a nesting box. Fat-tailed gerbils enclosures can be enriched with various wooden or ceramic toys, and they always require an exercise wheel (8" diameter minimum). It is common to keep fat-tailed gerbils singly (as they often display aggression towards housemates). Only a small percentage of keepers house them in pairs because of this. Although they are called 'gerbils' they are from a separate family to  most other gerbils and jirds and they are more like hamsters in their habits and enclosure requirements. Keeping a breeding pair can be somewhat difficult as most pairs squabble a lot when together, or they will live together peacefully but then don't always produce pups. Behavior. Wild Fat-tailed gerbils are sociable animals, and sometimes live in colonies, but can also live solitary (alone). In the wild, fat-tailed gerbils become active at dusk and this is the same in captivity - although they can sometimes appear to be diurnal. This gerbil species is active for some very short periods  in between longer periods of sleep, and they are very deep sleepers. Fat-tailed gerbils are very docile and almost never bite. They have a habit of hitting out with their front feet when hiding under something which can look like 'trying to bite' - but isn't. People say even that wild fat-tailed gerbils that are trapped can even be handled right away without being bitten. They seem to lack the curiosity of the Mongolian gerbil, and behave more like a Syrian hamster. Fat-tailed gerbils spend a lot of time grooming their fur and washing their face. They  like to dig a lot and dig in sand or other similar substrates. They also enjoy running on solid exercise wheels - so much so that it has become an essential part of their husbandry requirements. When they fight, they shriek loudly and bite each other's tails. The mating ritual of the fat-tailed gerbil may also be confused with fighting. Fat-tailed gerbils, like most other rodents, have scent glands on their stomach and engage in marking their territory by stretching out and rubbing their bellies on the ground and furnishings. Their scent markings don't seem to be  discernible to people and there is no noticeable odour from their cage unlike hamsters or mice. Breeding. Fat-tailed gerbils are sexually mature when they are 2 months old (sometimes before) and in captivity they can reproduce the whole year round. The gestation period of the fat-tailed gerbil is 19-21 days. Their average litter size is 3 to 6, and the pups are weaned at 3–4 weeks. Breeding fat-tailed gerbils in captivity can be hard, as the females can be very aggressive when they are pregnant or nursing pups. They can attack the male, and even kill  their mate if he is not housed separately after mating has taken place - although some can live together throughout. The chance of a female housed with a male becoming pregnant is much less than it is with Mongolian gerbils. A proven method to breed fat-tailed gerbils is putting a male and a female together in a rather small enclosure with nothing else in it than some bedding material. No nesting box, nothing to play with, no food dish. This way there is really nothing the animals can fight about. They can't become territorial because of the small space  and because there are no points to use as demarcation. With this method it is needed to keep the male and female together for at least one week (or before the male exhibits serious injury) and then separate them. Female fat-tailed gerbils are able to rear their litter alone. The mating ritual of the fat-tailed gerbil is rather unusual. Both males and females stand on their hind legs and wrestle, squeaking. They never seem to actually bite each other, but they get rather rowdy. If the female is not receptive and the male doesn't give up, the  female will turn and kick bedding at the male or bite his tail, often making it bleed. The female will make a nest and may get a little nippy when she is ready to have her litter. They are good mothers. Sexing. The difference between a male and a female fat-tailed gerbil is the same as with other small rodents. This difference can be seen at the distance between the urinary and anal openings. The distance between these openings in male fat-tailed gerbils is much larger than it is in females. Adult males have a large bulge at  the base of the tail that is their scrotum. So their testicles are clearly visible. This is totally absent from females. When the pups are about 2 weeks old the hairs on the belly start to grow and bald spots can be seen on the belly of the females. These are her nipples. These bald spots are absent in males. Colour mutations. It appeared that in Japan and other places (over 10 years ago) either a grey (g) or chinchilla (chm) mutation appeared. This fat-tailed gerbil was greyer in colour. But not everyone was not sure that it was  a colour mutation. It was possible that these grey fat-tailed gerbils were from the Egyptian subspecies "Pachyuromys duprasi natronensis". The juvenile coat of these gerbils was very grey but faded with age to a much more sandy colour. Some hybrids of the Egyptian and the Algerian subspecies have this grey coat as well, although it does lighten with age but is still greyish. Nothing else was known at the time, and has not since reappeared anywhere. More recently (2021) there have been images circulating online of 2 white duprasi pups of which little is known currently. They are potentially  leucistic in appearance. Purchase. Duprasi are very rare in the pet market, so they are not available in many places. In some countries they are not available; in others they are rare (Germany, France, Denmark, US and the UK), but in some countries, like the Netherlands, they are quite common. Occasionally, they can be found in a pet shop, but most won't have them. Ailments. A healthy fat-tailed gerbil has bright eyes, is lively, and has a soft coat. They are dry and clean. Sick fat-tailed gerbils get lethargic and are not lively, also their tails can  look deflated. Preventing illnesses is usually more effective than curing, especially for the fat-tailed gerbil; curing them is usually difficult. Fat-tailed gerbils are so small that even vets do not always know how they must treat the animal. Catching a cold can be fatal, although the biggest threats for a fat-tailed gerbil are draught and moisture. Hyperthermia, improper diet, and stress can lead to health problems. Not much is known about diseases of fat-tailed gerbils, because this small rodent has not been kept as a pet that long and often. But small rodents often have generally  the husbandry-related ailments. An ailment that can often can be seen in fat-tailed gerbils are bite wounds at their tail, because fighting fat-tailed gerbils try to bite in each other's tail. Teeth trouble is quite common too and can cause sore eyes, weight loss and over-grooming of the face.