The Hamster

Classification of the hamster

Order Rodents (Rodentia)

Suborder Miomorfi (Myomorpha = similar to mice)

Family Cricetidi (Cricetidae)

The Order of Rodents are the most numerous of the Class Mammalia, with more than 1,400 different species ranging from the tiny pygmy mice weighing only 18 ounces, to the capybara that can weigh over over 154.32 pounds. Rodents are divided into three major suborders: Sciuromorfi, Miomorfi, Hystricognath. The Family of Cricetidi is the largest with about 550 species. The most commonly that are found on the market belong mainly to three genres (Mesocricetus, Phodopus, and Cricetulus).

The Many Names of the Hamster

There is still a lot of confusion with the identification of the range of hamsters on the market. The main hamster breeds you will find are Golden, Russian Winter White, Campbell, Roborovskii, and the Chinese Hamster.

For proper identification, it is advisable to call them by their scientific name to avoid making further confusion to the already evolving, taxonomic classification of biologists. Here are listed the proper scientific names:

- Mesocricetus auratus (golden dorato)
- Phodopus sungorus (Russian Winter White; also known as Djungarian and Siberian hamster)
- Phodopus campbelli (Campbell’s hamster)
- Phodopus roborovskii (Roborovskii hamster; also known as Desert hamsters)
- Cricetulus griseus (Chinese hamster)

Throughout different stores you may also happen to come across "European hamsters". The European hamster is considered an endangered species due to the decrease of habitat from being hunted to rid it of its existence in cultivated fields. It’s of considerable size and has in common all the major characteristics of the other mentioned species (its nocturnal, generally lives alone, digs tunnels, etc.)

The Origin of the Name “Hamster”

The word "hamster" can be traced back to the Middle High German word "hamastra" which is more than likely from the Old Church Slavonic word "chomestoru". The word "chomestroru" derives from a combination of the Russian word "chomiak" and the Lithuanian word "staras", both meaning hamster.

Legislation of the Hamster

The five species of hamsters are all subject to free trade. It is not necessary to have documents for the sale or purchase of these small pets.

Getting to Know the Hamster: Morphology

All species of hamsters found on the market have a medium-small body size, ranging from 5 cm and 0.49oz - 0.71oz (Phodopus roborovskii) to 13-15 cm and 3oz - 5.29oz (Mesocricetus auratus).

The body is completely covered by thick fur, and skin that is very elastic and plentiful. The legs are rather short and the front two are equipped with only four fingers (the first is vestigial), where as the hind legs have five fingers each. Hamsters are equipped with long whiskers representing organs of tactile sense for when moving in the dark. Their eyes are very prominent and their ears are thin and delicate.

Their main characteristic are their cheek pouches, which are formed by an evagination of the inner wall of the cheeks and serve the purpose of transporting food into their burrows. These pouches are very expandable and can hold many seeds.

The dental structure of a hamster includes 12 teeth, four of which are incisors; two upper and two lower. These are very long and sharp and a vital tool for the hamster to be able to open seeds for consumption and also to use as a defensive weapon. The incisors grow throughout the life of the hamster and never stop growing in order to assist with everyday needs at their full potential. The incisors normally appear a golden-yellow color and the lower two are slightly longer than the upper. Also in the dental structure are then molars, which make up the other eight teeth. These do not grow continuously as the incisors do, but instead stay the same size throughout the hamster’s lifespan.

Hamsters do not have sweat glands. For this reason, they are very sensitive to high temperatures and can fall victim to heat stroke quickly.

Hamsters have a few special glands that can be found on the outside of their body. The golden hamsters (Mesocricetus auratus), specifically, have two glands on each side called the flank gland that are often mistaken for tumors because of the dark color. Meanwhile, the Russian hamsters (Phodopus sungorus, Phodopus campbelli, and roborovskii), have a ventral gland that is located on the ventral surface of the abdomen and navel, and can appear as a "crust" that often worries inexperienced owners.

Determining the Sex of a Hamster

Determining the sex of a hamster is not difficult as long as the animal is accustomed to human contact. We always recommend to double-check the hamster’s sex despite if the shopkeeper is certain of the gender. With small pets, it often happens that the pet that was originally was thought to be a boy, surprisingly gifts to the world a beautiful litter…

We recommend that when handling the hamster, gender checks are done by adults only and with that, very cautiously. You want to bring the hamster close to you in cupped hands so that the animal cannot in any way jump from you ending up on the ground. Hamsters have no sense of height and it is very easy for them to slip unknowingly from your hands. While making sure that the hamster remains wrapped in either hand, your free hand will be used to push aside the hair from the genitals so that you are able to get a better glimpse. It’s important to not blow on the belly of the hamster to move the hair, as the breath for some animals is equivalent to an attack.

The images below also demonstrate how to easily determine the sex of your hamster and the same methods can be used to determine the gender of all hamsters.

It is worth noting that the inguinal canal of the hamster is always open, thus males can retract their testicles into their abdomen. In golden hamsters, the ratio of testicular mass to body mass is the largest in the animal kingdom.



Male Hamsters

Looking at the picture on the left, the first arrow from the top shows the ventral gland (which in males is more visible and may be yellow or brown, since it is used by the hamster to mark their territory), the second arrow shows the male’s genital organ, the third shows the anus. In all male hamsters, of any kind, the penis and anus are located about one inch apart.

Female Hamsters

The image on the right shows how to recognize the female. The first arrow from the top shows the vagina, while the second arrow shows the anus. In all females of any species, the vagina and anus away are only a few millimeters away from each other.

Behavior

The behavior of hamsters reflects their status as prey in nature.

Hamsters are shy and reserved until they feel safe and they then become very social and explore incessantly their territory. If alerted, they will take shelter immediately in their den though. Thanks to the fact that many are handled continuously by people from birth, they have grown much more relaxed and many hamsters harbor full confidence in their owners allowing them to handle them quietly without showing any sign of discomfort.

The best in terms of behavior are the male, golden hamsters (Mesocricetus auratus). Because they are a larger breed, they are more easily handled, and are less resilient then the other breeds.The most difficult to contain are the Roborovskii hamster, who have a more lively temperamentand are more active.

They are crepuscular animals, so they increase their activity as the sun goes down and all night until early morning, when they then retreat to their dens for the rest of the day. Their main activities are directed to the care of their coat, the exploration of the environment, and hoarding food after carrying it inside the cheek pouches form the source into the den where it is stored.

A particular behavior, common to other small animals and the rabbit as well, is coprophagia (consuming their feces or other’s). They use this to supplement their diet, vitamins, and proteins produced by the metabolism of their intestinal flora.

Some breeds of hamsters live in very numerous colonies (Djungarian hamster and Campbelli).Others prefer to live in family groups or small groups (Phodopus roborovskii). And then there are the ones that choose to live completely isolated except during the breeding season (Mesocricetus auratus). For these reasons, captivity is not recommended for the breeds that prefer groups of 2 or 3 hamsters unless you have a cage of appropriate size (the Russian hamster for example). The Golden hamster is a breed that prefers to live alone though and therefore would enjoy a solitary habitat.

Hamster’s Lethargy

Hibernation is a natural process that some animals implement in order to overcome the cold season when food is scarce. It’s a very complex process and can be challenging to the animal. In addition to the lowering temperature, the gradual decrease of the daylight hours creates more stress for the animal.

During hibernation the body temperature is lowered, and the heart rate slows as well as the respiratory system. All this serves to save as much energy as possible. Hamsters can decrease their heart rate from 350-400 beats per minute down to 5-10 beats per minute. In early hibernation, they use shivers to heat their body.

Even hamsters in captivity are able to hibernate.The important thing to allow this is to gradually change the climate in order for them to adapt easiest. The simplest method is to put the cage somewhere on the outside terrace, subjecting the hamster to natural fluctuations of the climate. This allows the implementation of the techniques that will allow overcoming the instinctive drives throughout the winter months.

The hibernation of hamsters is defined from other species because they do not remain asleep for the duration of the winter season, but instead wake up more or less regularly in order to eat and drink, bringing the body temperature to a normal level for a limited period of time.

CLICK HERE TO OPEN RELATED PAGES
SPECIES Golden, Winter White, Campbell, Roborovskii, Chinese, European.
purchASE/adoptION When to buy, selecting a healthy pet, most common errors.
HABITAT The correct cage, terrariums, items to avoid, best advice.
DIET Most recommended/what to avoid, descriptive tables.
DISEASES AND CURES Communication, main diseases, most common errors.
REPRODUCTION Mating, delivery, distinguishing the gender.


Many thanks to: Dr. Sergio Silvetti, DVM
Associate of SIVAE-AEMV

Bibliography:
- K.E. Quesenberry, J.W.Carpenter: ferrets, Rabbits and Rodents, clinical medicine and surgery, Saunders 2nd ed.
- M.Avanzi: i Criceti, morfologia, carattere e comportamento, acquisto, alimentazione, riproduzione, salute, sintomi e principali malattie. De Vecchi editore, 2001
- R.M.Nowak: Walker’s mammals of the World vol. II, the Johns Hopkins University Press, 1999