Winter White vs Campbells: How To Tell Them Apart
The Winter White (P. sungorus) and the Campbell (P. campbelli) are commonly confused with each other, as many fail to be able to visually detect the differences between the two species. To many, they almost look identical - but when you know what you're looking for, both these species possess different very obvious traits that easily distinguish the two apart.
Distinguishing based upon physical traits:
The above photo is one of an Agouti Campbell's. Note their large ears, and more pointed snout. Other than colour, the ears and nose are often a dead giveaway of whether an individual possesses more Winter White traits, or more Campbells - keep this in mind when looking at our next example. Overall, Campbell's have a very mouse-like appearance. Now, let us look at an example of a Winter White:
The above photo shows an example of a Sapphire Winter White. If you compare this hamster to the one shown previously, you may notice some very obvious differences - most noticeably with the ear size & nose shape. Unlike the Campbell's more pointed snout, the Winter White has what we refer to as a 'Roman Nose'; the snout is shorter, and curved. Additionally, unlike the Campbell's more mouse-like ears, the ears of a Winter White are much smaller in comparison. There are conflicting reports on ear size (some say the campbells have larger ears, other say the winter white has larger ears), but it is generally agreed that it is the Campbells who have larger, mouse-like ears.
If we look at the eyes of the two hamsters above, you may also notice a visible difference in their eye shape. This can sometimes be difficult to notice when you don't have the two species in front of you to compare, but the Winter White has more circular shaped eyes whereas the eyes of the Russian Campbell are more oval.
Other than facial characteristics, there are also some physical differences in the coat of the hamster. The above photo is one of an opal Campbells dwarf. I will draw your attention to this hamsters side arches, where you will notice the very heavy yellowing on the side arches. The opal Campbells is frequently confused with the Sapphire Winter White, but this heavy yellowing is not present on the sapphire Winter White and so the two can easily be distinguished based on this trait (or lack thereof on the Winter White) as it relates to this specific color.
As you can see, this hamster lacks the extreme yellowing on the side arches shown in the hamster previously but has a similar fur colouring: this is a Sapphire Winter White and we can identify this by not only looking at facial features (such as the roman nose, and small ears which you can see on the hamster pictured above), but by lack of the heavy yellowing on the side arches.
An additional identification tool you can use to identify species is dorsal stripe width: the dorsal stripe of the Campbells (opal Campbells pictured above) is very obviously thin, and noticeably much thinner than that of the Winter White.
To compare a similar colour, I will compare a Sapphire Winter White to the Opal Campbells pictured previously. If we compare this hamsters dorsal stripe, you will note it is noticeably thicker: the dorsal stripe of the Winter White is at least 1mm wider than that of the Campbells. They also have a darkened 'diamond' shape pattern on their head (though this is much more noticeable on a Agouti and sapphire Winter White than it is on many Pearl Winter Whites where it is often not visible at all).
The darkened 'diamond' shape is much more obvious on the Agouti (pictured above) and Sapphire Winter White than it is on the Pearl where it often isn't visible at all. This darkened diamond shape on the forehead is a trait of the Winter White and is not seen on Campbells - though it can show up on hybrid dwarf hamsters.
In the case of Pearl Winter Whites, they are distinguished from white varieties of Campbell's based upon facial features, along with the thickened dorsal stripe. Pearl Winter Whites will always have a dorsal stripe, whereas several white Campbells will not.
Turning White is Not an Indication of Species:
Being in the hamster community for over a decade, I could not tell you how many times I have been asked by someone if their hamster was a Winter White based upon the fact that they had started becoming lighter or similarly, have been asked if their hamster was Campbell's because it didn't change colour. Now we will discuss why relying on whether or not your hamster turns white/drastically lighter is not an indicator as to whether that individual is a Winter White or Campbell's.
As hinted in their name, Winter Whites will turn white in the winter. However, not all Winter Whites will make this change in captivity. This is because they change their coats in response to daylight hours; shorter periods of daylight indicate to the animal that winter is coming, and they turn white in response. In captivity, there is the interference of artificial light and so many Winter Whites do not change coat because they simply do not realise that winter has come. It is also worth noting that Winter Whites can technically change colour regardless of the season. As it is a change in response to daylight hours, they can change colour in Spring, Autumn, or even Summer - so long as they have short hours of light. If your Winter White does turn lighter, the change is only temporary, and the hamster will change back into their usual coat when they believe winter has passed.
What some don't realise is that there are also two Campbell genes that will cause the animal to turn drastically lighter and unlike the change seen in the Winter White, where it is only temporary, the colour change in the Campbell's is permanent and often progresses until the animal is entirely white. These two genes are known as Platinum and Silvering and they are 100% related to the Campbell's and has absolutely no connection to a hamster being hybridised/partial Winter White.
The above photo is one of two Campbell boys I personally adopted back in 2014. The darker boy is what is known as an Opal Platinum, and the lighter boy is what is known as a Black Platinum. Note the band on their neck/back region (it is a little more difficult to see on the lighter of the two but if you look closely, it is there). This is a very common indicator of a hamster possessing the platinum gene, which is progressive and will drastically change the appearance of the animal as they age.
Would you believe me if I told you that the two hamsters in the above photos are the exact same ones as we just discussed? Because they are! As you can see, the platinum gene has completely changed their coat colour, turning both boys much lighter - and turning the Black Platinum hamster entirely white. It is not detrimental to the health of the hamster, and just alters their coat colour.
Similarly to platinum, Campbells can also possess what is known as the Silvering gene. Likewise, this gene is progressive and completely harmless to the health of the hamster. It is very commonly seen in black Campbells in particular, and is suspected to be linked to the black gene.
The above photos show a Silvering Black Campbells and a Black Campbells. These are photos of two different individuals, but show what the silvering black would have looked like before the silvering progressed.
So, as we have discussed, relying on whether a hamster turns white or not is not indicative of one being a Winter White or Campbells.
Identification Based on Colour:
The reliance on coat colour as an indicator can also make things rather difficult. While there are only three officially recognised varieties of the Winter White known as Agouti, Sapphire, and Pearl (pictured examples at the start of the blog), this is only as it relates to purebred individuals. Up until 1984, the Winter White and the Campbells were believed to be sup-species of each other and consequently, were frequently interbred. Due to having the same number of chromosomes, the Winter White and Campbells are the only known hamster species capable of interbreeding and producing viable, fertile offspring which we refer to as 'hybrids' (due to being a product of two entirely different species). This has resulted in very few purebred individuals remaining (of which can only be purchased from ethical breeders, with proof of pedigree) and has led to the creation of several 'new' varieties and the debates of the origin of other colours. One such example of the debate of origin is seen in the 'mandarin' variety, shown below:
Many will assume that the hamster pictured in the above two photos is a Campbells hybrid based on the colour, but this assumption would be incorrect. This is where relying on colour alone makes things rather complicated as while the hamster above isn't a recognised Winter White variation, she still shows entirely Winter White traits; note the small ears, and roman nose and because of this, it would be classed as a Winter White Hybrid. The colour shown here is Mandarin and there is a whole lot of debate on the origins of this colour made complicated by the interbreeding of species. There are several yellow-ish varieties found in Campbells (i.e. Argente, beige, fawn, etc) however Mandarin is not one of them - it is not a gene found in Campbell lines. It is also not officially recognised as a colour variety found in Winter Whites, although there is some debate that it is a mutation that was originally found in wild lines as it is a dominant gene that is not found in the Campbell. However, due to the interbreeding of species, hamsters possessing this colour variety in the pet trade are largely agreed to be hybrids as they have become so popular in Asian countries that even if these lines were ever pure, they have been destroyed by improper breeding practices. Additionally, several health concerns have been linked to this variation including being prone to obesity, diabetes, and kidney failure. These problems have been so wide-spread that it is regarded as unethical for a breeder to intentionally breed for mandarin and so regardless of true origin, the Mandarin variation is now regarded to be a hybrid.
While the hamster above was a more easy example on how relying on colour to identify species is not necessarily accurate, let us look at a more complicated one:
Take a look at the hamster above. Can you identify her? If we apply identification tools discussed earlier to assess this hamster, this hamster has:
a) a thickened dorsal stripe - Winter White characteristic
b) small ears - Winter White characteristic
c) red eyes - Campbell characteristic
d) yellow colouration - while there are 'yellow' variations of Campbells, this hamster is mandarin: as discussed earlier, the origin is debated surrounding the mandarin variety but it is believed to have originated from the Winter White
So, what would you call this hamster?
As the hamster above shows a majority of Winter White traits (thickened dorsal stripe, facial characteristics, and mandarin variation) she would be referred to as a Winter White hybrid; this colour specifically is known as 'Red Eyed Mandarin Pearl' and is a hybrid variety and so not an officially recognised colour. You can see more examples of purebred Winter Whites and Winter White hybrids here, and purebred Campbells and Campbells hybrids here. Overall, this is why I do not rely solely on colour, and instead use a combination of assessment tools for the identification of species (or species the hamster more closely resembles) as the hybridisation of dwarf hamsters has led to individuals often possessing the traits of both species - but, they often lean more heavily to one side than the other. While the hamster just discussed has red eyes, which is a Campbell trait (red eyes do not have origins in any purebred Winter White lines!), she possesses more Winter White than Campbell characteristics with her colour, dorsal stripe, and facial characteristics being more Winter White and so, it makes the most sense that she is either referred to as simply a 'hybrid' or a 'Winter White Hybrid' rather than a Campbells hybrid. Likewise, in the case of a hamster who physically displays more Campbell traits, these individuals are often referred to as Campbell Hybrids. There are many individuals who may possess equal traits of both species to the point where they do not lean more heavily towards one species than the other. In these instances, that is when we see the term 'Russian Dwarf' used most frequently or simply 'Russian Hybrid' or 'Hybrid'. Ultimately, all Winter Whites and Campbells who have not been purchased from an ethical breeder with proof of pedigree should be assumed to be hybrids and should not be bred from.
If you apply the methods of distinguishing a Winter White from a Campbell's mentioned throughout this post, can you identify the above hamster?
a) no dorsal stripe: this is common in white varieties of Campbell (Pearl Winter Whites have a visible dorsal stripe!)
b) pointed snout - Campbells trait
c) larger ears - Campbells trait
d) red eyes - Campbells trait
Physically, this hamster shows more Campbell characteristics and as such this individual would be referred to as a Campbell Hybrid. While this hamster does not show any Winter White characteristics, they are still referred to as a 'hybrid' as due to improper breeding practices discussed earlier, any Winter White or Campbells without proof of pedigree - regardless of appearance - is assumed to be a hybrid. For pet purposes, if you have a hamster who entirely looks like one species; for instance, in this case the individual looks entirely Campbell, whether or not you refer to them as a 'hybrid' really does not matter (it is only important for breeding practices that you never breed a hybridised hamster). I am only mentioning hybrid for the sole purpose of this post, to show how many hybridised individuals will lean more strongly to one species than the other. This is not always the case, and some individuals can look like an equal mix of both species but for others, who lean strongly towards one side more than the other, it is often possible to identify these hamsters beyond simply 'hybrid'; i.e. Winter White hybrid for those who look mostly Winter White, and Campbells hybrid for those who look mostly Campbells as mentioned previously.
So are they any health concerns associated with hybrid hamsters?
I surveyed 169 hybrid dwarf hamster owners. Of this sample size, 53% said that their hybrid dwarf hamster experienced no health problems that could be associated with the hamster being poorly bred. The remaining 47% said that their hybrid dwarf hamster did experience health problems that they believed to be associated with the hamster being poorly bred. 78% of those who said that their hybrid hamster experienced a health problem that they believed was due to poor genetics stated the health issue experienced by their hamster. The breakdown of those health issues experienced was:
Unexplained sudden premature death (<1 year): 17%
Eye issues (abnormally small/large eyes, early onset cataracts, etc): 8%
Unexplained obsessive aggression/obsessive behaviour: 7%
Organ Failure: 6%
Dental issues: 4%
This survey was conducted via instagram poll, so please take it with a grain of salt. It is not specific to Winter White hybrids or Campbell hybrids, and includes both species. While effort was made to eliminate false results, it is not flawless.
While a hamster being a hybrid doesn't guarantee health problems, and likewise a hamster being a purebred doesn't guarantee it to be exempt for experiencing health problems, it is important to keep in mind that any animal from an unethical source (as hybrids always are) is at increased likelihood for health issues. Other issues that may arise from breeding hybrids include issues birthing young due to the difference in head shape between the two species that can prove fatal to the mother. This is one of the primary reasons for why it is considered unethical to intentionally breed for hybrids.
As you may have noticed from this post, identifying a hamster purely based on colour often results in a mix-up of species as there are colours & patterns found in both species that may closely resemble each other to the untrained eye along with the breeding of hybrids which has created hamster who have physical traits of both species. This is why I personally recommend looking at both physical characteristics such as nose shape, eye shape, and ear size (not always reliable, but can sometimes help!) in addition to the animals coat colour when wanting to identify the species - or in the case of hybrids, when wanting to identify the species they most closely resemble. For the average pet owner, mixing up the two species isn't that big of a deal. After all, they are just a pet you have no intention of breeding. However, it can be beneficial to know as hamsters who lean more heavily towards: Campbells have more of an overlap in habitat with the Roborovski for example, and so may benefit from a larger sand area than a Winter White. You can read more about that over here.