Abnormalities of the hair follicles. These can be congenital or acquired. With congenital problems the cat's hair disappears within four weeks of life, or else are born without any. If the ...

Cats are known for ... some way to eliminate the bald patch to see if it affects hunting success. [I'm] not sure how you'd do this [and] I am not aware of anyone who has studied these bald patches." ...

This baldness is now on his hind legs and starting on his rump. It is not completely bald but patchy and has new fur in some places.