Meet Cinder, the "Naked Chimp," at the Saint Louis Zoo. Cinder was born with a beautiful, full coat of hair but at just five months old, started to lose her hair until she was completely bald!
When she was about five months old, we noticed that Cinder was losing some hair. She continued to lose her hair and in a definite pattern, first from her lower body and gradually extending up until after close to a year, Cinder was completely bald. We invited veterinary and medical doctors to consult with our veterinarians while we ran a variety of diagnostic tests. She was treated for a brief time with suggested medications, but in the end nothing helped. Cinder was diagnosed with alopecia areata, which “is a highly unpredictable, autoimmune skin disease resulting in the loss of hair on the scalp and elsewhere on the body.
Cinder's parents, however, didn't care one bit:
Cinder has never been treated differently by her parents or foster siblings. Beauty is in the eyes of the beholder and hair is not essential quality in the eyes of our chimpanzees. Indeed, Cinder was doted on by both parents to the point that we viewed her as spoiled. Mollie attended to her every need and refused to go anywhere without Cinder. The two slept in the same nest for years, longer than most chimpanzee mothers and daughters. Smoke was a playful father, ready to tickle and gently wrestle with his daughter whenever she was in the mood.
http://www.stlzoo.org/yourvisit/thingstoseeanddo/thewild/fragileforest/whoswhoinourchimpanzeefami/cinder.htm - via Blame It On The Voices