Introduction
For a number of reasons, the six species of Mouselike Hamster are arguably the most unusual of all hamsters. The first thing you notice about this hamster is that it bears a tail that is longer than its body (other species of hamsters, of course, have very short tails). It also lacks that most characteristic asset of hamsters, the cheek pouch. Although not a highly social animal, it nonetheless does seem prepared to tolerate other individuals of the same species, in contrast to many other hamsters that are firmly antisocial. So atypical is it from all other hamsters, that it is placed in the subfamily Sigmodontinae (or the Calomyscinae; opinions vary), rather than in the Cricetinae to which the majority of hamsters belong.
Mammalogists fail to agree on how many species of Mouselike Hamster exist. The current consensus is that there are half a dozen species, of which the commonest in captivity appears to be Calomyscus mystax – popularly known as the Iranian or Afghan Mouselike Hamster – and C. bailwardi, but some experts recognise only one species (C. bailwardi) which, they say, incorporates all the others. There is much to be said for this argument, since all the species occupy roughly the same geographical area and several species’ ranges do overlap. Being something of a ‘lumper’ rather than a ‘splitter’, I find myself erring towards the view that most species of Mouselike Hamster are not sufficiently distinct from one another to assign them full species status and, at best, should be thought of as merely subspecies. Everyone agrees that much more work is urgently needed in this area.
Mouselike Hamsters have been, and perhaps still are, used in Russian laboratories, and have appeared in U.K. collections only comparatively recently following the importation of animals by zoological gardens.
Description
A small animal. Head + body length 60–98 mm; tail length 70–102 mm; weight 15–30g. As its name suggests, this animal bears a strong resemblance to a mouse, not only with regard to its diminutive size and long tail (albeit thickly furred and terminating in a tufted point, unlike a mouse’s typically hairless tail), but also with its very conspicuous, large and erect ears, which are distinctly unhamster-like. The silky coat is pinkish buff, sandy brown or greyish brown on the upper parts. The belly is white, as are the legs and feet. The tail is dark above and white below. The hind legs are long, not dissimilar in appearance to a gerbil’s but more attenuated. As stated above, cheek pouches are absent. Females possess six mammae.
Distribution
Calomyscus bailwardi (Mouselike Hamster) – central and southwestern Iran, Caucasus, Turkmenistan, Afghanistan, northern Pakistan;
Calomyscus baluchi (Baluchi Mouselike Hamster) – eastern Afghanistan, western Pakistan;
Calomyscus hotsoni (Hotson’s Mouselike Hamster) – western or southwestern Pakistan;
Calomyscus mystax (Afghan or Iranian Mouselike Hamster) – southern Turkmenistan, north-central and northeastern Iran, northwestern Afghanistan;
Calomyscus urartensis (Urartsk Mouselike Hamster) – northwestern Iran and adjacent Caucasus;
Calomyscus tsolovi (Tsolov’s Mouselike Hamster) – only recently discovered in southwestern Syria and initially thought to be a subspecies of C. bailwardi.
Natural Habitat
Found mostly at elevations of between 400–3,500 metres on barren, scorched hills that offer numerous narrow crevices in which to secrete themselves, but in monsoon areas forsake this desiccated terrain in favour of hillsides clothed in evergreen oaks. The habitat associated with this animal may be the reason it lacks cheek pouches, because unlike other hamsters it is less likely to be caught in the open by predators – there is usually a crevice nearby into which it can vanish – and therefore there is less need for food to be transported back to the relative safety of the burrow to be consumed.
Social Structure
In the wild, individuals frequently share favourable shelter sites, where they huddle together for warmth. Captives, too, sleep huddled together like this and, although it cannot be thought of as truly social, in captivity it lives happily in pairs or even trios if the area is sufficiently large. I have kept a non-breeding trio in a 36" glass tank for well over a year, and I have never witnessed any aggression between individuals. Compare this with the behaviour of other hamster species. A pair of Syrian Hamsters, for example, can never be kept together, except when young or very briefly when the female is ‘on heat’, and, although other species like the Chinese, Roborovski and Dwarf Russian Hamsters will live as pairs for much of the time, the peace is very unstable and one has to be constantly alert to signs of fighting.
Temperament
Like most small rodents, the Mouselike Hamster does not enjoy being handled but, in my experience, never attempts to bite.
Behaviour
It does not seem to be as exclusively nocturnal in the wild as most other rodents. Admittedly, during the summer months it is active only during the hours of darkness, but in autumn and winter it can be seen foraging by day as well. This may be because less food is available at this time of year and more time needs to be spent in trying to obtain it if the animal is not to starve. Captive animals are very curious and quick to come out to investigate sudden noises in the vicinity of the cage. They are adept at climbing.
One peculiarity of this animal which, I confess, I have not witnessed myself, is what appears to be mutual-feeding. Some keepers record seeing individuals feeding each other. An animal will nuzzle the mouth of another that has just been feeding, until it opens its mouth sufficiently for the first animal to take food from inside. Adult animals have even been known to feed nursing females that refuse to leave their new-born babies to venture out to find food for themselves. I must admit I do have my doubts about this.
Locomotion
Mouselike Hamsters move fast and can jump at least 12" in height. When running at speed, the tail is carried slightly clear of the ground.
Vocalisation
Mostly silent. Communicates in a series of high-pitched twitterings.
Sexing
The anal-genital distance is approximately twice as wide in the male, compared with the female.
Accommodation
The best type of housing is a large glass aquarium with a well-fitting, secure, mesh lid. A glass tank 4 ft x 1.5 ft x 1.5 ft high is certainly not too big for this very active animal. Although the accommodation I provide for these rodents is smaller than this, it is equipped with a second ‘floor’. Other people have kept them quite successfully in laboratory-type cages but these have a major disadvantage that they are not big enough. The substrate can be of sand or phenol-free wood shavings. It need not be very deep as these animals rarely show any inclination to want to burrow. A generous quantity of cage ‘furniture’ should be provided in the form of rocks, tubes, branches, boxes, cardboard rolls, coconut shell, etc. if stereotypic behaviour is to be avoided. Strips of non-bleached paper can be provided for bedding. Provide a dish of chinchilla sand every few days, as these animals enjoy a dust bath and it helps to keep the soft, fine coat in tip-top condition.
Diet
Omnivorous. In the wild, Mouselike Hamsters feed on seeds, flowers and leaves. Although seeds and plant matter comprise the bulk of the diet, it is not above adding animal matter to the menu on occasion, and readily consumes insects and even carrion. In captivity a good basic diet consists of the following mixture (all in roughly equal quantities):-
Rodent breeder pellets
Flaked maize
Crushed oats
Sunflower seeds
Budgie seeds
Wheat
Peanuts
To this can be added small quantities of fresh fruit or vegetables, as well as such treat items as cooked rice or egg. Mine display a penchant for slices of apple and generally receive some every other day. Bristol Zoo offers its Mouselike Hamsters a small amount of dried fruit soaked in liquid paraffin to prevent constipation. Insects such as crickets or meal-worms that have been dusted with a multi-vitamin powder can be given two or three times a week and are much appreciated, in particular crickets as these prove a little more difficult for the hamsters to catch, thus providing occupational therapy. Clean, fresh water is essential, even though these animals do not appear to drink a great deal.
Breeding
A seasonal breeder in the wild. The breeding season, both in captivity and in its natural habitat, appears to be quite long, commencing in late March and lasting for most of the rest of the year. Some books erroneously state that it breeds only until early June, but this appears to be untrue, or at least not always the case, as field workers in Iran have found pregnant females in July, half grown males in early August, and lactating females in August and December. Since the young develop at a much slower pace than all other hamster species, I am wondering whether late breeding is a result of the previous litter being lost to predators or the vagaries of the weather. It is also possible that the length of the breeding season varies according to species and geographical range. In captivity, where the animal has an extended photoperiod and does not experience the harsh weather conditions it would in the wild, it is as likely to breed throughout the year.
Two litters per year are the norm. The female makes a ball-like nest from fine grasses and sheep’s wool, not dissimilar from a Harvest Mouse nest, in narrow horizontal crevices on rocky outcrops. In captivity a coconut shell or hollow log will be readily utilised for this purpose. The gestation period is approximately 21 days. Three to five young are born in an average litter, but in exceptional cases there can be as many as seven.
The young are born naked and blind. Eyes open at around 13 days. The youngsters’ first coat is grey in colour. Weaning starts at about 17 days, and the young are independent at 21–30 days. They become sexual mature quite late, at 116 days, but are unlikely to breed at this age. The first coat moults out at about 6–8 months of age, to be replaced by their adult coat. They are fully grown by this age, too.
Health
Care should be exercised when applying certain medications on these animals. I know of one female breeder whose vet prescribed a chemical spray of some description (I know not what sort, presumably an anti-fungal or anti-mite spray) to combat severe alopecia that was affecting three of her animals. This unexplained hair loss had started on the head area of each animal and progressed until all three animals were almost completely bald, and what little fur remained on each animal had what she described as a ‘damp’ appearance to it. Fortunately my friend tried the spray on just one of the affected animals and not the entire group, because the animal suddenly collapsed soon afterwards and died within three hours of receiving the treatment. Now I don’t know whether this was just a coincidence, or whether the spray provoked an allergic reaction. Nor do I know whether this specimen was just unfortunate or whether insecticidal/fungicidal sprays affect all Mouselike Hamsters in the same way. Perhaps the veterinary surgeon simply got the dosage wrong (an all-too-easy thing to do with such a small animal), and perhaps, at a smaller dose, the animal would have been fine. But I include this story as a cautionary tale to be wary of using topical sprays on this animal. Lifespan
2+ years.
Conservation Status
Unclear and contradictory. Rarely seen in the wild today, some field workers warn that the Mouselike Hamster may even be approaching extinction in the wild, although others report it to be relatively abundant. Until more field studies are undertaken, we must conclude sadly that of the six species, Hotson’s Mouselike Hamster is endangered, and at least three others (the Afghan, Urartsk, and Tsolov’s Mouselike Hamsters) are Near Threatened. For this reason, it is essential that more people try to breed this interesting taxa in captivity. There is still much about them we do not know, and observations of captive animals may provide us with this information.
