10 week old guinae pig

Question
Hi

We got a guinae pig for my daughter 3 days ago, it spent most of the 1st day hiding.  On the second day I noticed it had a bald ear.  The guinae pig is only 10 weeks old a friend said that the pig could have lost the hair due to stress, but i'm worried it might be mites or something.  The pig doesn't scratch or shake it's head.

Many thanks.

Answer
Guinea pigs naturally have no hair on their ears, except most have some hair in the inside of their ears, depending on the guinea pig's genetic it can also not have hair behind the ear. As long as the guinea pig is not scratching and does not have hairloss in any other areas like on the back or neck then it should be fine. Another pig could have also chewed on the hair by the ears also. Ear mites usually make a lot of crusty substance inside the ear and cause itching. Regular mites almost always first occur on the back or neck.
Brittany