At what age should a male puppy’s testicles descend?

The testicles of the male dog (like the ovaries of the bitch) develop inside the abdomen, but in contrast to the ovaries they normally descend through the inguinal canal to lie in the scrotum – a pouch of skin between the thighs. This is because for the testicles to produce sperm (i.e. for the dog to be fertile) they must be kept at a slightly lower temperature than that of the abdomen.

This descent is very gradual but in the majority of dogs the testicles are in the scrotum either at birth or within the next ten days. In some dogs they descend later, but if descent is going to take place it is always before six months old and usually the testicles are in the scrotum by three and a half months old. However, there are dogs in which up to nine or ten months old one testicle can readily be withdrawn from, and returned to, the scrotum. In early life the small size of the testicles may make detection difficult; however they can usually be felt by two months old, although sometimes not before they begin to enlarge (prior to puberty) at about four months of age.

Read the rest of this entry »