Fur biting occurs when a chinchilla is nervous or upset. You will notice parts of the fur
are shorter than the rest. In very bad cases you will find small bald spots. (If you see scaly
skin read the thread about fungus) Try to think about what has changed in your chinchilla's
daily life. (i.e. a new cage, a new pet, a move to a new room in your house, a fan blowing
on him) Once you have figured out the problem and taken away the stress, the fur biting
should stop and the hair will grow back in. Make sure he has a box of some sort to go
into to hide and feel safe. You can give your chinchilla treats of papaya to stop fur balls
from forming in his stomach. Many people believe that fur biting can be causes by a
genetic nervous disorder. If your chinchilla has been biting from an early age or can not
be cured by changing something in his environment its best not to breed the chinchilla.
If a chinchilla don't have a genetic cause but bites for an extended period of time due to stress
it can become a habit just like a person who bites their finger nails. Once the habit is formed it can
be impossible to break. Thankfully it isn't harmful, just cosmetic.
HOWEVER...
Sometimes fur biting can be caused by pain. If you can't pinpoint a stress that brought on the change
check your chinchilla for any sign of injury, watch for lack of eating and drinking, and take your chinchilla
to a vet if you see any other changes.