If this behavior happens out in a free-range environment with intact cats, or if we see it on a nature program, it’s something we understand as normal animal behavior. However, when it’s a neutered male cat attempting to mount a female or even another male in the household, it causes concern for many cat guardians. Even more upsetting for human family members is when the cat decides to start humping a visitor’s leg.
Some Reasons for Mounting Behavior in Neutered Cats
For most cats, this type of behavior stops after being neutered. The behavior may not stop immediately after castration surgery though. It may take weeks and in some cases, months or even years. After being neutered, there is a dramatic reduction in testosterone levels but the hormone is still present just as a reduced level of progesterone will still exist in the system of the female cat.
Even after being neutered, the male may become stimulated enough to try to mount a nearby female cat in heat due to her scent. A neutered male can even display mounting behavior toward a spayed female. Veterinary behaviorist, Nicholas Dodman, has suggested this may have something to do with the fact that the female doesn’t smell like a male. Since intact males can detect the odor of a female in heat from a distance, the fact that the female, although not giving off the scent of being in heat, may have enough of a scent to trigger the male.
Cats neutered at an older age may be more likely to engage in mounting behavior as well.
Mounting behavior in neutered cats can also be an attempt at reinforcing status.
If you allow your neutered cat outdoors he may encounter an unspayed female and her scent may be enough to trigger the behavior.