Your cat is acting weird. Is he doing what you think he's doing? That's a little gross, a little funny, and definitely disturbing. Intact male felines are sexual to a degree, but some excessive or inappropriate behaviors signify hypersexuality. It's important to visit a vet and ferret out the cause.
Most intact male cats display some degree of sexuality. They'll seek and mount female cats -- especially those in heat, who raise their back ends to offer their genitals. Hypersexual male cats, however, mount inappropriate partners. They'll mount kittens, other male cats, inanimate objects and (blush) even their owner's arms or legs. They'll mount the same animal multiple times, digging their claws in during the act itself, and they'll even occasionally masturbate, according to Bonnie V. Beaver's "Feline Behavior."
All of this can be quite awkward and even disconcerting, but there's an even better reason to suss out the root cause of hypersexual male cats: It can also indicate a serious medical condition.
Hypersexual male cat behavior varies in degree and by situation. Mounting of male cats, in many cases, is simply a social dominance cue when one cat invades another's territory. Kittens often mount each other too, although the play is usually broken up by an estrous female cat (i.e. one who's in heat). Other hypersexual behaviors can be caused by environmental deprivation or undersocialization. An intact tomcat who doesn't have access to an appropriate female cat often acts out his hormone-fueled sexual desires in atypical ways. Feline masturbation and the mounting of inanimate objects is most common when young male cats are isolated from others -- especially in laboratory conditions -- according to studies cited in "Feline Behavior."
Research in this field is ongoing. Until recently, hypersexual behavior in feline males had been solely associated with brain-damaged cats, according to a 1961 landmark study in the journal "Science."
Brain damage and tumors can cause hypersexuality in male cats. Some conditions are operable; others aren't. Expect a litany of questions and preliminary tests from your vet to rule out other possible causes of the behavior before a scan is ordered. Tests can be expensive, and may require special equipment. A regimen of drugs and hormone therapy can curb some behaviors, but they won't necessarily address the root causes. Moreover, behaviors that start because of medical conditions are ingrained socially and may require extensive retraining.
Hypersexual behaviors can manifest differently depending on their exact cause. Amygdaloid lesions (a specific kind of brain tumor) were once thought to cause a higher volume of sexual behavior, but as it turns out, only cause cats to mount less appropriate partners or objects -- not necessarily with more frequency, according to a 1979 study from the American Museum of Natural History. Other physiological systems may be involved: Cats given p-chlorophenylalanine, a synthetic amino acid related to the generation of serotonin, also develop hypersexual behavior, according to a 1970 study in "Science."
The Neutering Option
Testosterone is the ultimate arbiter of all aspects of feline male sexuality. One way to curb hypersexuality -- indeed, all non-social sexual behavior -- is to have your cat neutered. Both The Humane Society of the United States and the American Society for the Prevention of Cruelty to Animals recommend neutering (or spaying) your cat, first and foremost to keep down the pet population. There's more to it than that, though. Neutering your cat reduces his aggressiveness, reduces his urge to spray and mark territory, and also diminishes the pungent smell of his sprays. Regardless, if you're concerned about your male cat's sexual or hypersexual behavior, consult your vet and review your options. In the meantime, you might want to isolate him from other cats who don't appreciate his advances.
Always check with your veterinarian before changing your pet’s diet, medication, or physical activity routines. This information is not a substitute for a vet’s opinion.