Reasons for mounting behavior in dogs

N.H. Sunday News - Dog Tracks Column - 5/16/10
By: Gail T. Fisher


A reader writes: “My two-year-old Peek-a-poo/Pom weighs 24 pounds—about six pounds overweight. He’s been neutered, is very good natured, and is very friendly toward people and other dogs, although he is intimidated by larger dogs. He plays with two, three, and sometimes four dogs of similar size in a fenced area where they can run around and chase each other. The other dogs are of similar size. None have been altered. Every time they get together, the others try to “hump” him. What can I do to prevent this, other than not letting him play with them?”

While I prefer the word “mounting” to “humping,” in its proper context, this behavior is related to procreation. However mounting behavior is not always about sex. I started thinking about the causes of this behavior a few years ago when I was editing film my staff and I had taken of dogs playing in our daycare yard. Prior to this, I had thought mounting was either sexual or dominance. But as I soon realized from watching video of our play yards, there are myriad reasons for mounting behavior, and most are neither sex nor dominance.
Mounting behavior starts quite young. It is not unusual to see young puppies mounting littermates. Practicing this instinctive behavior is part of the puppy’s learning curve—in part learning to be rebuffed when a littermate turns on her brother saying, “Quit that!” teaching him to be a gentleman. Such early learning will be part of the dog’s adult behavior repertoire, so when he approaches a female who is not receptive, he’ll get the message and respond appropriately.

Unfortunately, this lesson is not universally-learned. A puppy may not have this early experience, may not have been rebuffed, or perhaps the scolding wasn’t sufficiently impressive to have a lasting impact. And of course, hormones may overpower learning.

The hormone testosterone plays a role in mounting behavior. Both males and females produce testosterone—males obviously producing more. Testosterone is produced in both the testes and pituitary gland. We accept unneutered males in our daycare, but if mounting becomes an issue, we will give the owner the choice to neuter and continue daycare, or to remove their dog from our daycare. Neutering—surgical removal of the testicles—reduces testosterone levels in the average dog, and often reduces or eliminates male mounting behavior.

Female mounting is a different story. Some bitches actually begin mounting after they are spayed, likely because the pituitary gland produces testosterone, and spaying has removed the female hormone estrogen that mitigates the male behaviors.
There are several other possible causes of mounting beside hormones. Possible causes we’ve observed in our daycare yard include strenuous play likely causing overstimulation, one dog trying to get another dog’s attention, or trying distract a dog from a different playmate, and new dogs may be mounted apparently as a way of “making friends.”

In our daycare playgroups, we discourage mounting behavior by simply calling the mounter’s name. Usually that is enough to interrupt the behavior unless the dog being mounted is what we call a “mountee”—a dog that is mounted a lot. Such chronic “mountees” often have a urinary tract infection, which attracts other dogs. When we notice one dog being mounted a lot, we will suggest a veterinary visit to check for a UTI, in which case treatment usually cures the problem.

For the reader, I would suggest ruling out the possibility of a UTI. Other solutions are training—for the other dogs’ owners to teach their dogs to be responsive to being called off. And finally, neutering may help, but the reader may not be able to convince the other owners to do this just so they can play with his dog.

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