On a beautiful, warm afternoon, I watched a group of dogs frolic in a dog park. Suddenly, I heard a woman’s high-pitched yelp, followed by the pounding of human feet. There was no need to look; it was obviously about humping, which we can also refer to as mounting.
Dogs hump the air, they mount pillows and blankets, and they can be found poised behind the neighbor’s dog or befriending Uncle Joe’s leg but not Uncle Albert’s. Mounting pops up in many contexts and is directed toward any number of objects, both animate and inanimate. Apart from giving mounters silly nicknames like “the humping bean” or “Sir-humps-a-lot,” what are we to make of all this bumping and grinding?
Talking about dog behavior is like talking about politics: everyone has an opinion. According to Cynthia Heyman of Utah, her three-year-old Danish-Swedish Farmdog, Jet, is a play-humper. “Jet is intact, and he likes to hump when he plays. He seems to like the boys better than the girls. Last weekend, he was humping a neutered Aussie who humped him right back as they were playing.”
For Margaret Duclos of Seattle, Wash., mounting is related to excitement and arousal. “One of my dogs sometimes humps the other when we get into the car — usually only when it has been a few days since we’ve gone somewhere and he is especially excited.”
On the other end of the spectrum, some attribute humping to dominance. Brigitte Reed of Salt Lake City, Utah says, “My female dog, Snickers, who is spayed, will hump our male dog, Kitna. The reason being is she is alpha and she is asserting her dominance over him. Putting him in his place, as it were.”
When a dog’s a humper, there’s inevitably an owner nearby with a story, usually one that describes who or what is mounted (the stuffed animal, the cat, other dogs) and the context in which the humping occurs (when guests come over, at the dog run, during obedience trials). Owners postulate that sex, breed, age, reproductive status and even size might provide information about humpers. Most of these stories culminate in questions — “Why in the world does she do this? Aren’t males the humpers?”— or impressions, anything from “It’s just play” or “She’s dominant” to “He’s quite popular!”
As you might expect, animal behavior researchers have a lot to say on the topic. When exploring any behavior, we can turn to the insights of Nobel Prize–winner and famed ethologist Niko Tinbergen for help. Tinbergen’s “four questions” provide a reliable framework within which to understand why animals behave the way they do. One of Tinbergen’s questions is particularly apt: “How does a behavior develop during an individual’s lifetime?” After all, behaviors don’t simply fall from the sky, land on a dog and voilà! Mounting! For nearly as long as ethologists have studied dogs, they have taken note of dogs’ tendency to hump outside of reproductive contexts.
In the early 1970s, University of Colorado ethologist Marc Bekoff, PhD, began investigating the development of canid social behavior. Bekoff observed the interactions of young canids, pairs of three- to seven-week-old wolves, coyotes and dogs. Particularly among the dog puppies, mounting, clasping and pelvic thrusting appeared early on in play. While males mounted more than females, females also engaged in aspects of the behavior. Dr. Sunil Kumar Pal, assistant teacher at Katwa Bharati Bhaban School in West Bengal, India, got similar results when investigating social behavior of young, free-ranging domestic dogs. By six weeks, both male and female puppies were mounting, clasping and pelvic thrusting.