There is little physical variation among hamsters -- they generally share the same fluffy fur, tiny black eyes, little paws and stubby tails. One of the most easily recognizable and distinct features of a hamster are his cheek pouches. Hamsters are generally considered hoarders, and are known to stuff their cheeks full of food. Their cheeks also serve another evolutionary purpose, though, which can help them when danger lurks.
Hamsters love to eat, and when not in captivity, they find their food by scavenging and returning to the nest with their findings. They use their cheek pouches to store and carry food, like a grocery bag that they always have available. A hamster can hold about half his body weight inside his cheek pouches, and when they're fully stuffed, the cheeks are about twice as wide as the animal's head and shoulders.
Hamsters don't just stuff their faces with food -- they can also pack up their cheek pouches with babies. Mother hamsters are protective of their babies, and when they perceive a threat to the newborn clan, she may stuff the babies into her mouth and hide the babies in her cheeks. She'll hold them inside until the danger is gone, which is sometimes longer than the babies can survive inside her mouth -- they may suffocate while she waits for the threat to pass.
A hamster's cheek pouches stretch to impressive sizes so that they can accommodate large stores of food or even live newborn hamsters, but this also makes them a highly sensitive, delicate part of the body. In particular, the cheek pouches are susceptible to punctures from sharp objects. Like a stretched-out balloon, the cheek pouch's malleability comes at the expense of toughness, and this particularly thin layer of skin can be pierced with relative ease.
Because of the hamster's tendency to stuff his cheek pouches full and store whatever he can inside, you have to be careful with what he has access to. For example, the lining of his cage can be problematic -- lining with a cotton wool consistency can get impacted in his pouches, while pointed lining material like straw can puncture the delicate skin. The food you give him can harm his oral health, as well. If you give him sweets or milk products, for example, he may stuff them in his pouches and hold it there for extended periods, damaging his teeth -- it would be like if you spent the day sucking on sugar cubes.
- syrian hamster on abstract white background image by Maximillian-Setislav from Fotolia.com