Because of ignorance or greed, there are numerous hybrids dwarf hamsters in captivity. Unfortunately, these hamsters are at risks and moreover, the two species they come from.
In the wild, Russian hamsters (Phodopus sungorus) and Campbell’s hamsters (Phodopus campbelli) never meet. Indeed, the Russian hamster lives in Central Asia (Mongolia, Dzungary), while the hamster of Campbell is most often found in China. However, in captivity, hybrids are very common because of ignorant people or even unscrupulous breeders. This hybridization causes many problems.
What is a hybrid?
First of all, what is a hybrid? A hybrid is the result of a cross between two species. Here are the species of hamsters we know in captivity:
To our knowledge, only the Russian hamster and Campbell’s hamster can hybridize because they have the same number of chromosomes (28) and these chromosomes are similar in size and morphology. However, some chromosomes show structural differences and that’s what is causing numerous problems.
Where do these hybrids come from?
The first cause of hybridization of dwarf hamsters is ignorance. How could a beginner make the difference between two species that are very similar?
The search for profit is also at stake, with pet shop managers who do not care about the pedigree of rodents and have them reproduce at all costs without any control.
Then, some breeders are also to incriminate. In 2006, for example, Dutch breeders reportedly mate Russian hamsters with Campbell hamsters. As the Campbells have a much wider colour range, the goal was to get new colors in Russian hamsters, which do not display a lot of colours. Breeders managed to obtain the following colour mutations: Tangerine, Mushroom, Orange, Brown, Moscow. Then they crossed these hybrids with Russian hamsters to fix these colours in the latter, destroying the purity of the lines. This is why in some countries these colours are banned from shows and competitions, since their carriers are not “purebred”.
What is the problem?
First of all, the health of the mother hamster and her babies can be put in danger before or during the birth. Indeed, there may be a difference in size of fetuses and placentas between two species. A scientific study has shown that a female Russian hamster that has been bred with a Campbell male will have embryos that are 38% heavier than any other type of cross. Even more striking: the placenta is 300% bigger!
With embryos, babies and an overdeveloped placenta, the risks for the young and the females are also enormous… Hybrid babies die during pregnancy or are stillborn. The worst case scenario is when the mother can not give birth because the babies are too fat and dies in terrible pain…
Conversely, the same scientific study showed that babies born from the cross between a Campbell mother and a Russian father were 40% smaller than their parents. However, this difference in size is observed only once at birth, and not during the embryonic development, which seems normal.
When hybrids survive, it is to have a short life, about 12 to 18 months, instead of 24 months minimum. They are very likely to suffer from diabetes, a disease that is unfortunately all too common in Campbell’s hamster. They can also be affected by many birth defects, including organic malformations invisible to the naked eye.
They may also have neurological problems. One of them is called “stargazing”: the hamster makes a “back flip”, when in fact it is his brain that is sick. There are also cases of backflipping, when the hamster can not stay up. Hybrids also show behaviour problems, they constantly repeat the same movements.
Breeders also report cases of aggression and nasty bites, which inevitably leads hamsters to be neglected, abandoned or euthanized.
On the fertility side, the two types of crosses (Russian female x male Campbell and vice versa) can produce sterile males and females with decreased fertility.
Finally, the breeding of hybrids to the detriment of each of the two species (Russian hamster and Campbell’s hamster) could lead to their disappearance. Unfortunately, a lot of hamsters sold in pet stores are hybrids … Moreover, few enthusiasts make the effort to find a good breeder while it’s so easy to just go to the local pet store.
How to recognize a hybrid Campbell x Russian?
First of all, be aware that it is often very difficult to recognize a hybrid for several reasons. It depends first on the degree of hybridization: does the hamster come from a single generation, or from several? What is the proportion of Campbell genes compared to Russian genes? What genes are activated, replicated, dormant? Impossible to know. A hybrid can look a lot like a Campbell or a Russian. And these two species are also very similar! When it’s hard enough to tell the difference between a Campbell or a Russian, it’s impossible to unmask a hybrid …
However, here are few key features:
- Hybrids have unique colours: Mushroom, Mandarin, Orange, Brown, Moscow. (And the Campbell Hamster has a lot more colours than the hybrid and the Russian).
- A hybrid can display the morphology of one species, but the colours of the other.
- A hybrid sometimes has defects like a surplus of skin, too big ears, or an irregular dorsal line.
- A hybrid sometimes has smaller eyes and a pointed snout.
- A hybrid often has diabetes, whereas it is rare in Russian hamster.
What to do if I discover that my hamster is a hybrid?
The first thing to do is to make sure he is in good health. Bring him to the vet, and test him for diabetes. If you find that your hamster is diabetic, you can give him fenugreek seeds and especially review his diet to eliminate any source of glucose.
Watch your hamster carefully and make sure he does not have any neurological problems. Enrich his environment to stimulate his neurons and avoid stereotypical behavior.
Then contact the person or pet shop that sold you your hamster to learn more about the dangers of hybridization.
How to stop hybridization?
There are some very simple steps to take … if only rodent enthusiasts were sufficiently informed, and if the stores did actually care about the origin of the animals they sell!
- Inform rodent enthusiasts about the dangers of hybridization
- Teach amateurs to try to recognize a hybrid
- Inform pet shops
- Stop buying hybrids
- Do not breed hybrids
- Do not cross Campbell hamsters and Russian hamsters
- Adopt Campbell hamsters or Russian hamsters from recognized breeders with pure lines
By Marie-Sophie Germain
POCKET PETS GAZETTE 