For male dogs, the benefits of neutering (
orchiectomy) are not quite as compelling, although it does decreased the risk of prostate hypertropy and infections pretty significantly and if the dog is going to be allowed out unsupervised it does help to keep the dog home and to avoid complications associated
with seeking out females in heat, such as being hit by cars, shot by angry female dog owners (maybe only a U.S. problem?)
Orchiectomy (neutering) is recommended in male chinchillas to reduce undesirable behaviors associated
with testosterone, prevent reproduction
with female in the house as well as to reduce the chances of reproductive tract disease.