Why Does a Hamster's Tail Curve to Its Back?

With their puffy cheeks and twitching noses, hamsters make cute and friendly pets. They communicate with one another and with us in different ways such as squeaking, yawning and stretching and sitting up. When a hamster sticks its tail straight up or curves it to the back, it's usually a sign your female hamster is in heat.

  1. Tail Anatomy

    • Syrian hamsters grow to a length of 7 inches, while dwarf hamsters reach 3 to 5 inches. They have short, stubby tails, typically 1/16 the length of the body, which may be difficult to see because of their coats. One exception, the Chinese dwarf hamster, has a long tail that's the full length of its body.

    Sex Determination

    • To see if the cause of the raised tail means your hamster's in heat, you need to know the sex of your hamster. Looking at the tail line can help you determine the gender. A mature female hamster has a trim, streamlined tail, while a male's tail bulges on both sides. If your hamster lets you, pick it up and look underneath. A male hamster has testicles and a scrotum sack, and a longer distance between the genitals and the anus than a female.

    Estrous Cycle

    • Female hamsters can be bred as early as 6 weeks of age. They come into heat every four days and, during this time, assume the breeding position of body stretched out, back swayed and tail up. If you hold your hamster while she's in heat and stroke her back, she becomes motionless and sways her back more.

    Wet Tail

    • A serious intestinal disease, wet tail, can kill a hamster quickly if not treated. Wet tail usually strikes hamsters at 3 to 6 weeks, but can affect hamsters of any age. If you notice a soiled, wet tail and symptoms such as watery diarrhea, lethargy, loss of appetite, failure to groom, hunched posture or dull, sunken eyes, take your hamster to the vet immediately.