Cat Behavior After Neutering

In general, older cats show more changes in behavior after being neutered than younger kittens who haven’t yet been exposed to hormones.

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Cat looks out window
Male cats often try to escape to seek out females. Neutering should help curb this behavior. Toni Perec/Shutterstock
Dr. Sandra Mitchell

Your neighbor has a lovely little kitten, Mr. Spots, and decides it is time to take him in to get his kitten shots. Almost immediately, the topic of neutering him surfaces. “But he’s only 3 months old,” Mr. Spot’s owner is thinking. “Does he really need to be neutered? How will his behavior change after neutering?”

Let’s find out what you can expect from a male cat after he is neutered.

Will my cat’s behavior change after he is neutered?

Well, the answer to that is yes — and no. Much of the answer depends on the age at which the procedure is performed. Cats that are neutered at a younger age are at a different hormonal stage of life, and therefore respond differently to being neutered than older animals who have already experienced the influence of hormones. Cats who have experienced hormonal influences show more changes than younger kittens who haven’t yet been exposed to the hormones.

What are the positive behavior changes I can expect?

Many intact tom cats (mature cats that have not yet been neutered) will start to mark their territory by spraying small amounts of very strong smelling urine around the house. Spraying in the house can happen even with indoor-only cats. Not only is this unsanitary, but it’s also hard to clean up. The spots can be hard to find, and Kitty may re-mark them as soon as you get the area cleaned. Many, but not all, cats will slow down and stop spraying after they have been neutered. Most owners consider this a very good thing!

Another unpleasant behavior seen by owners of unneutered male cats includes roaming and fighting, while they wander and seek receptive females. Indoor cats may spend time trying to escape, even ripping screens in the attempt to get out and defend a territory and look for female cats.

Unfortunately, not only do cats become injured during these ventures (think cat bite abscesses and being hit by cars), they can also be exposed to potentially fatal diseases such as feline leukemia (FeLV) and feline immunodeficiency virus (FIV, or Feline AIDS) through their exposure to other unneutered cats. The rate of both FeLV and FIV is significantly higher in the unneutered cat population.

Luckily, most cats will also cease these dangerous behaviors after neutering. This also decreases their injury rate, as well as disease transmission rates — meaning that neutered cats tend to stay healthier.

So, on the plus side, Mr. Spots is more likely to stay home, be healthier, and be a good kitty citizen after he is neutered.

Are there any negative behavior changes associated with neutering?

Once again, the answer is yes and no.

Many animals will experience a slowing of their metabolism after they are neutered, meaning that more of their calories will go to their waist as opposed to being burned off. As many of us have experienced as we’ve grown older, if you don’t adjust your caloric intake, it is much easier to gain weight as you age. Kitty is no different.

By neutering, we have essentially put Mr. Spots into “menopause” — we’ve stopped his natural sex hormone production. This can have the side effect of slowing the metabolism, causing weight gain.

Fortunately, this is very easy to avoid by adjusting how you feed a neutered cat. Simply making the change from dry to canned food may be enough to keep Spots slim and trim. If you wish to continue feeding dry food, portion control is the answer. Ask your veterinarian for help choosing a proper amount of food, but for most cats, a level one-third to one-half cup of dry food is adequate to feed per 24 hours.

What causes these behavior changes with neutering?

When a male cat is neutered, the veterinarian will remove both of his testicles. The testicles produce the hormone testosterone, which causes the sexually-related changes in cat behavior, such as marking territory (spraying), defending the territory (fighting), and looking for a female (roaming).

When the testicles have been surgically removed, the body no longer produces testosterone. It takes about 60 days for the remaining testosterone hormone in the bloodstream to be used up, so typically, the sexually-related behaviors start to abate over the first two months after surgery. Behaviors that persist after this time are learned behavior, as opposed to hormonal behaviors.

How do learned behaviours differ from hormonal behaviors?

With time, some cats learn their bad habits, as opposed to being mostly hormonally driven. For example, a cat may have started spraying urine in the house initially from a hormonal drive, but then it later became a habit to spray. For this reason, it is not guaranteed that all cats that are neutered will stop (or unlearn) these behaviors, but the primary drive behind them is removed.

These learned behaviors are a major reason that veterinarians recommend neutering kittens before they have the opportunity to experience these hormone surges and learn these unwanted behavior.

At what age should a male cat be neutered?

Most cats will start to experience some hormonal surges by 6 months of age (which, for most cats, is when they weigh 6 pounds). Therefore, it is generally recommended to have the surgery done prior to this time.

Most veterinarians agree that once both testicles have descended and the kitten is at least 3 pounds (which is 3 months old for most animals), it is safe to schedule to the procedure. This prevents any early surges of hormones, and as we all know if we have watched children heal, younger animals, just like younger people, generally heal much faster.

So what happened to Mr. Spots?

Mr. Spots owner realized that even though she had what she thought was a pretty young kitten, she actually had a near teenager on her hands, and that it was indeed time to get him scheduled for “the big day.” She was pleased to learn that he didn’t even need to stay overnight, and he could go home and be back to normal activity in almost no time at all! Armed with this information, Mr. Spots was scheduled for surgery right away as his pet mom didn’t want to take any chances with him developing any negative behaviours by not being neutered before the hormones started surging. Not surprisingly, he healed quickly – and all parties were pleased with the decision, even Mr. Spots!

Article Categories:
Behavior and Training · Cats