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Chinese
Hamster Article By Russell
Tofts N.B. Please note that the notes below refers to the subspecies Cricetulus barabensis griseus (sometimes elevated to full species status by some taxonomists), which is the one most commonly found in pet shops and in the home. Other Names Occasionally called the Striped Hamster, Striped Dwarf Hamster (not to be confused with the Russian Dwarf Hamster (Phodopus sungorus) which is also known by that name), or Chinese Striped Hamster. On rare occasions it has been called the "Mouster", because of a superficial resemblance to a mouse. Introduction Despite more than a passing resemblance in both size and appearance to the true dwarf hamsters (genus Phodopus), the Chinese Hamster is classified as one of about 6 species of "rat-like" hamsters (so-called because the configuration of the head is said to resemble a rat's). It appears more "streamlined" than the Russian Dwarf Hamster, being slender in build with a shorter, less dense coat, a longer, more flexible tail, more pointed nose and, in the case of the adult male, very prominent testicles. Its relative lack of popularity may owe something to its "mouse-like" appearance (sans the long tail characteristic of murines) and alleged reluctance to breed under controlled conditions. Owing to its tractable nature, this is one of my favourite rodents. Still comparatively rare in pet shops, it is not suitable for young children, being small, fast and agile, and easily harmed by rough or incautious handling. The keeping of this species is prohibited in certain states in America. Size The smallest of the "Rat-like Hamsters". Head/body length: 75-100 mm; Tail: 20 mm; Weight: 38-46g. Biology Body temperature 97-100º F. History in Captivity For a species still comparatively rarely seen in pet shops, the Chinese Hamster has a surprisingly long history in captivity. It has been kept by various laboratories and universities in the U.K. since at least 1919 and the renowned Dr Hsieh had some in his laboratory at the Peking Union Medical College, but early efforts to establish it as a laboratory animal were not encouraging and no where was it widely retained or bred until quite recently. The first animals were thought, erroneously, to be the Daurian Hamster (Cricetulus barabensis barabensis), an animal which looks very similar but has never really "taken off" as a pet. It is therefore possible that a few, misidentified, animals were present in captivity prior to 1919. This original captive population seems to have died out because most of the present stock is believed to be descended from animals captured outside Beijing (formerly Peking), China, in 1925. In 1948 ten pairs were exported to Harvard Medical School in the United States and another pair was received by the New York Zoological Park in 1952, but this latter pair proved to be so antagonistic that no breeding was possible and the survivor escaped after just 1 year, 11 months. It was not until 1957 that the species was successfully bred outside China, but it was only in the 1960s/70s - with attention turning to other hamster species besides the perennially popular Syrian or Golden Hamster (Mesocricetus auratus) - that there was renewed interest in the Chinese Hamster. It has oft been said that it is difficult to breed, hence its continued paucity in captivity. I should say, however, that I personally have never had any trouble breeding it. Colours, Patterns & Varieties My strong opposition to the breeding of animals, not just rodents, in colours and patterns other than the ones in which they occur naturally is well known. The present trend for producing different colour mutations to satisfy the personal whim of the breeder is threatening to dilute and eventually wreck the gene pool of so many captive species. I would therefore urge all owners to keep and breed only the original or “natural” colour. However, for the sake of completeness, I feel I should make some comment here on the artificial colours in which Chinese Hamsters are bred. The Chinese Hamster presently occurs in only a few colour variations. As well as the Normal Grey (my personal favourite), there is the Dominant Spot and, more recently, a White variety. The Dominant Spot was the first colour mutation to be discovered (at Birmingham University, U.K. in 1981/82). This animal produces smaller litters than the Normal Grey and, according to some experts, is slightly less aggressive to its own kind. It does, however, carry a lethal recessive gene, so two Dominant Spots should never be bred together. It is the presence of this "killer" gene which (a) is one possible reason why not more colours have been developed so far, and (b) is the factor that causes some of the foetuses to perish in the uterus, which seems to be a common problem with this variety. The White variety is even rarer. First seen in Germany or Switzerland (its provenance depending on which source you consult) in 1982, it is smaller than the Normal Grey. Development of this variety has been hampered by the fact that male Whites are sterile. It is suspected that, like the Dominant Spot, the White variety also caries a lethal recessive gene. The development of other colours is inevitable as the species becomes more popular. Even as I write, there are unconfirmed reports of the development of other colours including Albino (Albinos should not be confused with Whites), Argente and Sapphire. It may be no coincidence that the three mutations mentioned above (the existence of which I have not been able to verify) all occur very freely in the much more popular and widely kept Russian Dwarf Hamster, and I suspect may be the result of confusion between the two species. Distribution North-eastern China, possibly extending into parts of neighbouring Mongolia and Manchuria. Natural Habitat Like other "Rat-like Hamsters", it occupies dry open country, such as steppes or the edges of deserts but, as far as is known, avoids true deserts. Temperament In general, most Cricetulus species are aggressive and untrustworthy towards their human handler. The Chinese Hamster is an exception. They are lovely animals, friendly, and rarely bite except in extreme cases, although they can at first be quite timid until they get used to being handled. Immature animals in particular are nervy, fast moving, and will jump out of your hands without hesitation. Don't let this put you off, as they tame readily and by the time they are fully adult are slower and easier to handle. Chinese Hamsters are, however, often intolerant towards their own kind. Females are dominant and can be aggressive both to males and to other females, frequently quarrelling amongst themselves - particularly when pregnant or nursing young. Females not infrequently bite the tail and genitals of the male, in rare cases emasculating the unfortunate male. The keeper therefore needs to be constantly vigilant, taking appropriate action whenever bite marks are observed if serious injury or even death of the subordinate individual is to be avoided. Some females will also attack and kill sick, old or weakened specimens. Aggression can be lessened by providing an exercise wheel. Although some breeders advocate keeping Chinese Hamsters singly, putting them together only at infrequent intervals for breeding purposes, in my opinion it is better to maintain them as pairs, either true pairs or single sex. If breeding is not desirable, two males will live together better than two females. However, as this species is still relatively uncommon in captivity, it does seem a shame not to attempt to breed it, and so hopefully, in time, it may become more firmly established. Breeding results are better when these animals are kept in a pair, rather than in a colony. The colony system rarely works well for this species and usually disintegrates after a time due to fighting, particularly if there is more than one female in the group. There are, of course, exceptions to every rule and I have heard of at least one breeder who successfully keeps two males and three females together. This only proves that, when keeping animals, there are no hard-and-fast rules. Animals kept together as pairs pose special problems when one of the pair dies, as it can be very difficult to introduce a stranger. If the surviving animal is old, it is probably less traumatic to leave it on its own rather than risk an introduction but, if it is a young animal, it is worth trying to introduce a new companion. Introductions should be carried out on neutral territory and the golden rule is to introduce the female to the male, NOT the other way round -and be prepared to separate the pair immediately if fighting results. So just how antisocial is this species? Perhaps not as intolerant of conspecifics as one is led to believe. Well-known British rodentologist, Chris Henwood, advances the case that much of their aggressiveness is derived from in-breeding, where close relatives are mated to each other. Close pairing was practised extensively in the early years and specimens were notoriously difficult to manage together. But where the policy of out-breeding is pursued, much of the intolerance disappears. It should be said that, like many other rodents, specimens are opportunist feeders and will partially eat dead cage companions. The discovery of a mutilated corpse, therefore, does not necessarily mean that it was killed by its fellows; it may have died of natural causes. Behaviour Certain authorities report that, in the wild, this species is active both day and night during the spring and summer, but becomes increasingly crepuscular or nocturnal as winter approaches. Other sources state that it is mainly nocturnal but is occasionally active for short periods during daylight hours. In captivity I have found them to be exclusively nocturnal throughout the year, only rarely showing themselves during the day, but it is possible that the behaviour of captive specimens differs markedly from that shown by their wild cousins. In common with other small rodents, it has poor eye-sight but acute senses of smell and hearing. In its natural habitat the Chinese Hamster lives in burrows which it excavates itself. Some burrows have a single entrance hole while others have two or even three entrances. The complex burrows with multi-entrances are most likely to be the domain of experienced, mature animals, and it is probably younger individuals that are responsible for the simpler burrows. Within the larger burrows one finds the main living quarters and separate chambers for food storage and nesting. Although Chinese Hamsters are fiercely territorial, these burrows are often found very close to each other, giving the misleading impression of their living in colonies. Chinese Hamsters possess enormous internal cheek pouches. They collect huge quantities of food in their pouches, to transfer to their burrows to consume in relative safety. They are excellent climbers, using their slightly prehensile tail as an aid, although in most conventional cages they have little scope to demonstrate their arboreal prowess. In the wild, this species does not hibernate continuously but awakens from time to time to eat stored food. As the weather becomes colder, it enters deep-sleep and the intervals between spells of waking become longer. In captivity, as long as the cage is kept in a warm room, there is no reason why your hamster(s) should attempt to hibernate. If the room temperature drops too low, it may fall into a torpor-like state and may even appear to be dead. On no account should you allow this to happen. Sexing Even for the inexperienced eye, there is no mistaking the sexes. From as young as 8 weeks, males possess a very large (in relation to body size) scrotal sac. It is to avoid complaints or embarrassing questions from the public that some pet shops stock only females. For very young animals the best guide is the anal-genital distance, this being approximately twice as wide in the male as in the female. Females possess eight mammae. Why should the males be so well endowed? The answer seems to be what might be termed "sperm wars". In general one finds that the animal species with the largest testes, relative to body size, are those where there is intense rivalry for the females. Male Chinese Hamsters are promiscuous, and their testes have to be able to manufacture a prodigious amount of sperm in order to inseminate as many females as possible. The sperm is of good quality, vigorous and fast-swimming. It has to be in order to beat his rival's sperm in the race to fuse with the ovum. Compare this with a typical man's semen that contains a high proportion of malformed or lethargic sperm. In the human species, it does not matter if a mating does not always result in conception because most men are monogamous. If a male Chinese Hamster does not successfully implant the female, there are plenty of other males who will! Handling Their agility and small size means they are not suitable for young children. I would feel unhappy supplying this species to anyone below the age of 11 or 12 years. To pick up a Chinese Hamster, simply "cup" it gently in both hands or, if you are more experienced, you can use one hand, placing your hand over top of the animal and folding your fingers underneath it. Sit on the floor or handle the hamster over a table or couch, as even a short fall can prove fatal. Do not handle one that has just eaten, or you will find that in its shock at being suddenly picked up it empties its cheek pouches of seeds. This is an instinctive move to lighten its load for a quick getaway from what it perceives as a potential predator. Although a Chinese Hamster is unlikely to bite, it should be remembered that it does possess a capacious bladder, which the animal may empty over one's hands if frightened. Accommodation Chinese Hamsters can be kept in a large glass tank with a tight-fitting, wire-mesh lid. The key word here is "large". So quarrelsome are the females that only a tank as big as possible, furnished with plenty of "play" equipment, will allow the subordinate male any peace. A ten gallon tank is not too big. Standard commercial cages intended for the larger Syrian or Golden Hamster are generally not suitable, as the bars are set too far apart and escape is only too likely. There should be a gap of no more than 8-10 mm between the wires. Mouse cages are, in theory, adequate for this species, but you will find your choice severely limited in both size and design. Such cages are unimaginative, being fairly standard in design, often too low and usually lacking a second level. One advantage of conventional cages is that many designs have horizontal bars, thus affording these dextrous animals opportunity to climb. Whatever cage is finally chosen, make sure the water bottle is positioned at just the right height - not so high that these small animals cannot reach it but not so low that the spout is in constant contact with the substrate or you will find the water leaks out through capillary action. Position the cage in a draught-free position, away from direct sunlight and in an even "room" temperature. The optimum temperature is 21º C. but Chinese Hamsters are very hardy and are able, if necessary, to survive extremes of cold better than they can tolerate excessively hot conditions, and have even been known to breed successfully at a chilling 15º C., but plenty of dry bedding is an essential requisite if a cold spell is predicted. As with other animals, cold is always more dangerous when combined with dampness or draught. Interconnecting Hamster Housing These plastic cages, sold under a variety of trade names, usually consist of round compartments interconnected by a network of plastic tubes. To a child's eyes they may look fun but, in my opinion, these cages are totally unsuitable as permanent housing for most rodent species, although admittedly they are not as ill-designed for Chinese or Russian Dwarf Hamsters as they are for Syrian Hamsters. The cages are very gimmickry, overpriced, with poor air-flow on the hottest days, and contain too many plastic parts that can be gnawed by the occupant, in some cases permitting its escape. According to the manufacturers, the cages are designed to simulate the hamster's natural burrow system. I maintain that the basic starter unit is too small unless extended quite considerably by the addition of other compartments. Since they are designed like plastic bowls, these cages can in summer become unbearably hot for the occupant and condensation can make the inside rather damp. Chinese Hamsters may encounter some difficulty climbing up the vertical tubes and you may need to invest in a small metal ladder. Litter & Bedding Traditional wood flakes are still very popular, but can be dusty and there is evidence the sawdust irritates the eyes and mucus membranes. For this reason very fine sawdust (which, ridiculously, is still sold in some pet shops) should be avoided altogether. Pine wood, especially red cedar, is especially bad due to the aromatic nature of the wood. Constant inhalation of the phenol oils present in this type of wood can cause an allergic reaction and, possibly, long-term health problems. The high incidence of cancerous tumours in some rodents may be partially due to chronic exposure to these oils. Aspen wood seems to be safe, but unfortunately bags of wood shavings purchased from a pet store are rarely labelled with their source and it may not always be possible to ascertain the type of wood used. A new type of floor covering is a relatively new type of cat litter made from recycled newspapers. This is clean and easy to use, albeit not always easy to find, and does not seem to have any potential health risks like some of the more traditional wood-flake substrates. My favourite Chinese Hamster was a male by the name of "Reuben". He was given a "gerbillarium-type" environment (so-called because of its suitability as gerbil housing), i.e. a glass tank containing a deep (18-20 cm) layer of peat substitute (Coir fibre mixed with soft sand in a ratio of 3:1 together with a large handful or so of straw). The main entrance to his burrow was beneath a broken flower pot. He did very well in this set-up which allowed him to burrow as he would in the wild and he lived for 2½ years. Another advantage of this type of housing for those with little time on their hands is that (depending on the size of the tank and the number of inhabitants) a thorough clean-out of the tank, whereby it is stripped down, emptied of all its contents and washed out, might be necessary no more than about 5-6 times a year. Soft meadow hay is suitable for bedding and has the added benefit that it will also be eaten. Other suitable bedding materials include strips of non-bleached paper or tissue. Avoid anything that looks and feels like dyed cotton wool. This is sold in pet shops under a variety of brand names. According to the manufacturer's blurb, it is quite safe, but there is now increasing evidence that this is not true. Synthetic substances like this can be ingested and hamsters have been known to choke on it or for it to impact the intestines. Cage Accessories Provide plenty of toys and other furnishings to keep your animal(s) occupied. There is a wide selection available from pet shops, some much more suitable than others. Rope ladders and hammocks are good and stimulate climbing. Avoid anything too gimmickry. And don't neglect the importance of things you find around the house and garden, including cardboard rolls, flower pots, plastic tubes, tree branches, half a coconut shell, wooden cotton reels, etc. Provide at least two sleeping boxes so that your animal(s) has/have a choice. Finch nesting boxes are ideal for this purpose. The exercise wheel should be solid plastic and not the metal spoked design which can result in trapped and broken legs. If you have no choice but to use a spoked wheel, render it safer by weaving cardboard through the rungs. Some hamsters can become addicted to running in the wheel. If this is the case, it should be removed for a short time. Cleaning Out The faeces of Chinese Hamsters are dry and inoffensive (as you would expect with an animal that, in the wild, lives in a fairly arid environment and the need for the kidneys to conserve moisture is paramount) and cleaning out should not be necessary any more frequently than about once a week, or even less frequently in the "gerbillarium" environment described above. Chinese Hamsters are clean animals that usually choose one corner of the cage in which to urinate and defecate. This makes life very easy for the owner. But whenever you decide to clean out the cage, remember to replace a little of the old bedding, as this is impregnated with the animals' familiar smells. Hamsters rely to a large extent on their olfactory organs and a cage must smell like "home". Rodents can get quite distressed on being returned to their cage to find that it smells completely alien. If there is a cache of food stored in the nest, it is important to replace a small amount or the animal(s) will think that their larder has been raided by a rival. Feeding The wild diet consists mainly of young shoots and seeds, but insects are probably also taken from time to time. Captive animals should be given a small quantity of proprietary hamster mix and bird seed (such as millet or canary seed), with the addition of a few broken cat or dog biscuits, such as a puppy meal, and small amount of fruit or vegetable matter. Preferred food items include peas, soybeans and various millets. Hay is essential for its fibre content. Animal protein is also important. The most convenient way to give this is to add dried cat or dog food to the diet once or twice a week. Meal worms or crickets can also be offered or you might like to try small pieces of cooked meat. Unlike more sedentary rodents, Chinese Hamsters do not put on weight easily because of their busy lifestyle. Food consumption per day is about 10-15g, depending on a number of factors such as age, exercise level, or, in the case of females, whether the animal is pregnant or lactating. Beware of feeding too many sharp oats, as these can scratch the delicate lining of the cheek pouches. Limit carefully the amount of green food as an excess can result in diarrhoea, Sunflower seeds should be offered sparingly because, although relished, they can be fattening when fed in excess. Low in calcium, they have been implicated in cases of osteoporosis in some rodents. But this should not deter you from giving sunflower seeds. Like all foods, there is no problem when fed in moderation. Foods to avoid include garlic, raw kidney beans, onions, or rabbit mix (which may contain a coccidiostat). Treats to avoid include honey bars or chocolate drops - both of which are found in most pet shops - but soft or syrupy foods such as these can cause the hamster's cheek pouches to become impacted or even prolapsed. This is an example of certain manufacturers not having a clue about basic rodent biology. They launch a new product with scant regard for the welfare of the animal, simply because it appeals to the majority of pet-owners. Salt licks and mineral blocks, available from your local pet shop, are also much appreciated. A general vitamin compound can be given occasionally, as can added calcium for nursing females or growing young. It is important to provide wood gnaws. Like all rodents, hamsters' incisor teeth grow continuously throughout the animal's life and they require something hard to gnaw on to prevent the teeth becoming overgrown. Clean drinking water must be available at all times, ideally supplied in a gravity-flow bottle. Average water consumption is about 11-13 ml per day. Temporary lack of water is one factor that precipitates fighting. Health All illnesses are potentially serious, so at the first sign of trouble consult your veterinary surgeon without delay. Any sign of diarrhoea should be investigated immediately as dehydration in a mammal as small as this occurs rapidly. It must be said that some vets are much better than others at treating small mammals and it is a good idea to search out, and introduce yourself to, one of these rare paragons before your animal falls sick. Reproduction To repeat what I said earlier, in captivity this species seems to have acquired a reputation for being difficult and slow to breed, although I personally have never had any problem breeding them. In the wild, males appear to be fairly nomadic and visit several females' burrows in turn for the purpose of mating. A females signifies her readiness to mate by standing still and raising her tail when approached by the male. Females are capable of producing 3-4 litters per year. They come into season again almost immediately after giving birth. Oestrus Cycle: Every 4 days. Gestation: 20-21 days, but on very rare occasions it has been recorded as short as 16 days and as long as 30 days. Young (Cubs): Litters are small. On average 4-6 cubs are born every four to eight weeks. It is not uncommon for many more than six to be produced (or as few as two) but in very large litters neonatal mortality is high. The cubs are born naked and blind. Birth weight: 2-3g. Disturb the new-born babies as little as possible for the first two weeks as the nursing female is very sensitive to stress and, if frightened, she may cannibalise the babies. She usually excludes the male from the vicinity of the nest when the cubs are very small but sometimes lets him return as the babies grow. The cubs develop rapidly as can be seen from the chart below. 3 days old: Skin darkens The cubs should be removed from the parents at about 4-6 weeks. Chinese Hamsters mature late and, although physically capable of breeding sooner, in my experience they rarely mate under 12-16 weeks of age. Life Span 2-3 years on average, but can live up to 4 years. In general Chinese Hamsters live substantially longer than members of the other two short-tailed hamster genera regularly seen in pet shops, Mesocricetus (the Syrian Hamster) and Phodopus (the typical Dwarf Hamsters). |
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