Behavioral Problems of Unneutered Male Dogs

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Amy Marder, V.M.D.

A few years ago, Bob and Ginny consulted me because their beagle, Max, was “doing embarrassing things.” It seems that whenever their female beagle, Betsy, left traces of an oily substance where she’d been sleeping, Max would investigate it carefully, then jump on a pillow and mount it! To be sure, he had first tried mounting Betsy, but she’d snapped at him. He’d also given his owners’ legs a few tries, but they’d rebuffed him, too. Bob and Ginny were puzzled; Max had been neutered when he was less than a year old. He shouldn’t be doing these things, should he?

Behavioral Problems of Unneutered Male Dogs


I paid a visit to Bob and Ginny’s home so I could directly observe the dogs’ behaviors. Max was three years old at the time. With his broad head and large chest, he looked much more masculine to me than most neutered dogs. In taking a detailed history of the dogs, I learned that Max had been obtained from a friend when he was a little over a year old. He had been neutered by the friend’s veterinarian. At that time, Max had no problem behaviors. Sometime during the next year, he began to lift his leg in certain places in the house and run away every chance he got. When he was about two years old, he began to fight with male dogs. It was shortly after this that the mounting behavior started. Jumping on his pillow after sniffing where Betsy had been sleeping had developed over the past few months.

The Pillow Case
What was stimulating Max to do this? To find out, I rubbed every part of Betsy’s body with a paper towel and presented the towel to Max. It was only when I expressed Betsy’s anal sacs that I produced the problem behavior. Bob and Ginny confirmed that the fluid I expressed from Betsy looked like the oily substance they had been finding on their furniture and in Betsy’s bed. So I had my diagnosis: an unusual attraction to anal sac secretion by a very masculine-looking, macho-acting, neutered dog!

It’s not that unusual for neutered dogs to exhibit male behaviors, such as roaming, mounting, urine marking (leg lifting on objects) in the house and fighting with male dogs. Max, however, exhibited all of them, and frequently! Plus, he didn’t look neutered. To verify that he had been, I drew blood to have testosterone levels run. To everyone’s surprise, Max’s testosterone levels were those of an intact male!

At this point, I contacted the veterinary hospital that had performed Max’s neuter. The doctor who had done the surgery had left the practice, but the hospital’s records revealed that one of Max’s testicles had never descended. While this is not unusual, it’s very important if this happens that the testicles be removed. If one or both are allowed to remain inside the abdomen, not only will they continue to produce testosterone and cause the male behaviors that Max was displaying, but they also are prone to developing cancer. But in Max’s case, the records showed that rather than removing the testicle, the veterinarian had performed a vasectomy!

Peace At Last
My recommendation was to have Max really neutered. Studies show that no matter how old a dog is when he’s neutered, the results are the same: testosterone-related behaviors of roaming, urine marking, mounting and same-sex dog aggression decrease or disappear. I also recommended that Betsy’s anal sacs be expressed at least once a month so that her secretions would not leak out during sleep.

Max improved after being neutered. The roaming stopped altogether. However, not all of his male behaviors disappeared completely. Occasionally he still lifted his leg in the house and fought with other dogs. Keeping him confined to the kitchen when he was alone and supervising him at other times controlled the urine marking. Walking him on leash controlled the fighting. Bob and Ginny were overjoyed! And last but not least, their pillows lay unmolested on the sofa.

Dr. Amy Marder is vice president of behavioral medicine and head of ASPCA Companion Animal Services.

© 2000 ASPCA

ASPCA Animal Watch – Spring 2000