Why Do Male Cat Heads Shrink After Neuter. In cases where your cat has only recently had the surgery, this is simply a response to the hormones which are still present in the cat as they slowly decline. Male cats that are neutered also tend to have smaller heads.
Neutered male cats do not become ‘characterless’, dull, unintelligent after castration. They are less likely to spray and if they do, their urine smells much less strongly. Gender, breed, and body structure can cause a cats head to be small.