Why do male cats mount each other?

Dear Most Esteemed and Knowledgeable Kitties:

My two 8-month-old brother cats, are usually very loving and clean each other. Recently I noticed one of them won’t stop crying at night on our bed; then I caught the other one grabbing his neck with his teeth and apparently trying to mount his brother! The little brother had tears and was crying! I pulled his brother off him, but then he kept this up all night. I’m scared! Can my cat actually hurt and try to mate with his brother? I never thought this possible. Please help!


Dear Most Esteemed and Knowledgeable Kitties:

I have two cats, both male and altered. They are approximately 4 and 5 years old. I got both of the cats at the same time. The normally docile cat is mounting the other male cat. The other cat’s rectum looks red and inflamed. Is it actually possible penetration occurred? Is a vet visit necessary?


Thomas: I’ll start this one out. As the resident expert on male cat behavior, I’m exceptionally qualified to answer these types of questions. When male cats mount one another, it’s in an effort to establish dominance. Animal behaviorists refer to this as sexual aggression.

Siouxsie: We’ve seen this behavior not only in cats, but in the dogs, goats, and chickens we live with. Sometimes female goats will even mount one another to show dominance!

Dahlia: Sade, you don’t mention if your cats are neutered. If they’re not, neutering will serve to gradually decrease this behavior. However, if they are neutered but it only happened recently, give it time. It takes several weeks after neutering for the male’s testosterone levels to decrease to the point where there is little to no sex or dominance drive.

Thomas: Jenny, you said your cats are neutered, and presumably since they’re 4 and 5 years old, they’ve been neutered for quite some time. This is a pretty clear case of solely dominance-based behavior.

Siouxsie: But you both should know that neutering a male cat doesn’t automatically turn him into an it. Males still have some sex hormones circulating in their blood, even though that level is very low.

Dahlia: Like humans, cats have chromosomes that determine their sex. Male cats have an X and a Y chromosome, and female cats have two X chromosomes. The cat with an X and a Y chromosome has its brain bathed in testosterone as it develops in the uterus, which causes permanent changes in the structure and chemistry of the brain. The massive increase in the amount of testosterone at puberty fully activates these changes, but they don’t go away with neutering.

Thomas: Therefore, a male cat is always male and will continue to demonstrate some male behaviors even after he’s neutered.

Siouxsie: We’re 99% sure that anal penetration does not occur when male cats mount other males, because we don’t think it would be physically possible. Cats’ mating practices are designed to introduce the penis into the vagina, and the vagina is positioned lower than the anus.

Dahlia: In order for penetration to occur between male and female cats, the female has to assume a swaybacked position that points her genitals upward, and then she has to move her tail aside. This behavior is instinctive in female cats and typically it only occurs when the female is in heat and receptive to the male’s mating behavior.

Thomas: When male cats mount other males, generally the one on the bottom won’t “assume the position” because he doesn’t have the same hormonally and instinctually based response as the female. And generally, male cats don’t get erections when mounting other males.

Siouxsie: There are some things you can do to reduce or eliminate the mounting behavior, however. Dr. Nicholas Dodman, author of a number of animal behavior books including The Cat Who Cried for Help: Attitudes, Emotions, and the Psychology of Pets, says that using a pheromone treatment like Feliway (which comes in spray or diffuser form) can help to reduce the aggression that leads to this behavior.

Dahlia: Applying androstenol (a sex attractant for pigs) to the rump of the victim can also discourage unwanted attacks. I’m not sure how that would work, but maybe your vet would have a clue.

Thomas: You could also make the aggressor wear a large, loud bell so the victim can hear him coming and get out of the way. But remember, we cats can be pretty creative about removing such devices and learning how to move quietly even with a bell attached to our collars!

Siouxsie: Dodman also says that medicating the aggressor with progesterone-like compounds can be effective for temporary management of the behavior.

Dahlia: And finally, Dodman says that SSRI medications like Prozac can be used to manage aggressive behavior. We’d suggest you try the other methods first before resorting to psychopharmacology. But remember, if nothing else works, antidepressants or anti-anxiety medications can be an option.

Thomas: There are things you can do to stop this aggression behavior, and we hope that you’ll find one or more of these tactics to be helpful in managing your kittyboys’ behavior. Good luck, Sade and Jenny, and please let us know how things turn out!

  • Toni Neumann

    By the size of the victims anus & the sperm on his testicles, I’m quite sure he was penetrated & I feel sorry for him. I ‘m going to fix the agressor but you stated that May not work so I’ll ask my vet about medication.

  • Amanda

    I have a question as well! My male cat, weird as it might be, I believe has been in heat! I have not yet looked to see if there is both male and female genitalia, but I have the mother cat who got into heat again and he wasnt mounting her, but he was rolling around on the ground just like her, and then he got loose and we found him on the ground in the female position with a male cat mounting him! When done he just rolled and rolled around on the ground! I picked him up and his rectum was bloody, and we saw blood coming from around his testicals but it never hit me to look for an extra hole. I have note yet looked, in fear I might find him a hermaphrodite cat. I am so lost, what should I do and if there is no female genitalia then what is wrong with my cat, a family member said he could be a homosexual cat! But I have never heard of such a thing. Any advice would be nice! Thank you!

  • Charles


  • Abbi

    My two male kittens are not yet neutered and one is constantly mounting the other. However he only does it when his brother is lying down and just stands over him with his chin resting on his brothers head and both of them purr away. Its like a big brotherly snuggle, no agression at all. Soon as the younger one has had enough of being cuddled he just turns around and licks his brothers ears and the older one jumps off. Its quite sweet, although at first I was worried what was going on they both seem perfectly chilled out and happy.

  • BeBe

    Oh, man. This is a great article. THANKS!

  • Kate (kat)

    Cat mounting behavior.. wipe the hair between the shoulders (in the same place as you would put flea drops) with alcohol and gently blow it dry away from the cat’s head. The back of the neck will be distasteful to the aggressorr cat.

  • http://macadamiacreative.com Max Dancer

    Ha, both of my cats nibble each other on the back of the necks and purr.

  • Carbon

    I have found my cats doing similar things!
    I have two male tabbies – one is six years old and the other is about a year and a half. My older cat makes these cooing noises like a dove (he makes them when he’s looking out the window and sees birds and squirrels) just before he bites the neck of my younger cat and mounts him! It’s strange because my older cat is such a harmless teddybear and the younger cat is crazy and bugs the hell out of him. I actually don’t blame my older cat for asserting his dominance since it was his house first. He’s been doing this since we introduced the other as a kitten, but the mounting didn’t start until he was bigger. If I left them the younger cat starts to cry but doesn’t fight back and the older cat looks like he’s in a trance. Sometimes he won’t let go even if I interfere. I dunno. Boys will be boys i guess… just don’t understand the cooing!

  • Jaalo

    The dominance thing makes sense. I have two male kittens that are 4 month old brothers. Usually they are very loving and cuddling with each other. I have one that is a black and grey tabby and one that is part simese. The tabby was the first born and was the largest for the longest time. The simese was the runt and has always been tiny until now. My tabby is very laid back and calm and nurtures the simese and the simese is a rotten shit… Excuse my language. . . . there is no other way to describe Harlow. He is always sneaking around and hiding just waiting to attack someone or his brother. Even though Ziggy (the tabby) has always been larger he has never tried t dominate Harlow. Just recently though, Harlow has started trying to mount Ziggy. I hear Ziggy crying and I go in there and Harlow is doing exactly what the others have describe above. It seems as though even though Harlow is the runt, he has matured faster than his brother. He has started spraying already and seems to be trying to dominate too. The info above has been very helpful to me because I was really worried about my cats.

  • Audrey

    My two male cats arent quite brothers but they were born within a week of eachother to the same household and I got them at the same time. They’re my only cats. At first one was mounting the other from time to time but now the roles have been reversed and became more frequent. They are approximately 7 months old and not neutered. I tried the alcohol trick and that just seems to ward off the follow through but not the intent. Having them “fixed” would probably be an ideal option but I kinda have issue with it and would like to find a more natural solution.

    • Mikey

      Is it neutering that you have an issue with? Isn’t that better than the extreme over-population problems? The statistics on un-altered felines (male & female) are frightful.

      The reproductive rate alone is staggering. Add to that violence, disease and starvation — I can’t believe that anyone would think these are a better alternative.

      That is a truly frightening thought.

      • Uber

        Not having your cats fixed isn’t a problem if they are indoor-only. How about people be responsible pet owners and not let their cats run around outside unsupervised, Mikey? You wouldn’t let your dogs come and go as they please, would you?

        • Avonsídhe

          I am sorry but… Cats aren’t like dogs.. Would you put fish, snails, mice, raccoons, etc.. On leashes?? No.. Dogs are very different animals due to over breeding. And being bred to be a certain way. Yes not getting your cats fixed if they are indoor only does indeed cause problems.. If you knew cats at all you would know that they will spray or bleed everywhere. It is nearly impossible to get the smells and stains out.

  • http://facebook.com/dotbernardo dot

    my male cat is experiencing the same. is he gay? he wants to be raped by a male cat. now, there is something (puss or i dunno) in his anus. help!!!

  • kb1

    My 2 year old neutered male cat started this nonsense with our newish 8 month old neutered male kitten. They roughhouse a lot, but I found the older one biting the back of the kittens neck and doing a humping stance. I laughed my butt off at first, and then asked myself if my cat was gay.
    Reading the replies above, I realize it is just a dominance/sexual aggression thing, I will try the alcohol on the neck, though. Maybe also the Feliway products.
    P.S. It is still really funny, but I now swat him away when I see the humping begin. HA!

  • Avonsídhe

    Both of my kitties are neutered and one of them still rapes the other.. It is slightly a dominance thing but it is also arousal because his little Weener will come out as he rapes his brother and when I stop him.. His brother’s butthole looks gooey, irritated, and penetrated… Boy on boy sex definitely can and does happen between brother cats even if they are neutered.


    Two of my cats are really close, but has been a little more dominate, and mounts the other cat when hes asleep. T C will get a kitty woody but he only rubs on my other cats leg. Itty Bitty is a big cat so mostly he just lays there on his side half asleep and makes growly hissy noises when TC bites to hard. I walked over to them and said to TC “well are you done having fun?” He got this embarrassed look and jumped down and now hes laying on the other side of the room.


      Oh I forgot to day Itty Bitty has a blanket (we call it his “girlfriend”)
      He twists it up and does his thing. One of our friends came over and said “Thats just wrong…” but I think its all very normal for a cat.

  • Chelle

    Thanks for answering this. It was interesting and informative until the comment freaks turned it into a furry penthouse forum.

  • D Hall

    Have a neutered male being attacked when he goes outside by an intact male who looks feral. The feral has been coming around for about a year without too much trouble. Also have four spayed females; two are 9 mos old. All but two of the 5 cats go outside and stay within the fenced confines of a patio about 15′ X 20′. So far there are no injuries ti the females. But my neutered male cat has screamed several times lately and run to the door to get inside. I have gone outside to try to scare away the tomcat with imitation growling and aggressive verbal warnings. My cat had several areas of hair missing from his body near his rump last week. After the latest attack his rump area is actually swollen and appears painful. Has he been bit, or scratched, or worse?

  • Pam

    LOL!!! On the floor laughing at some of these posts!!! Question answered, thanks!

  • Amanda

    Both of my make cats are like this. My older cat Pogi will mount the younger 6 month old cat and hump him. But he doesnt penetrate Sid. His little pink thingy comes out and afterward there will be a big wet spot on Sids back tailside or by his top leg. And Sid just lays there let it’s normal. But thank you for the info I shall try the alcohol first. Thanks!