Do Neutering and Spaying Cause Depression in Pets? No Word Yet, But an Interesting Question

By Veronique Greenwood | October 10, 2011 1:17 pm


Hormones are major mood-regulators, as anyone who has been cranky before a period or had their reproductive organs removed for medical reasons can tell you. In fact, depression is a common side effect of such surgeries in humans. But does that extend to some of the most regularly de-hormoned animals out there—our pets? That’s the thought-provoking thesis of a recent Slate piece, and while there’s been no systematic research on how such surgeries affect cats and dogs, a smattering of research has suggested that having your supply of hormones eliminated does affect the mood of mice and primates, free of the confounding influences one finds in humans. Madeleine Johnson of Slate describes one set of experiments:

[Researchers in Japan] reasoned these snow monkeys could model mood changes due to ovariectomy without confounding variables like the social stigma of barrenness that might affect women. The center picked 10 females of equivalent rank in the dominance hierarchies and removed the ovaries and uterus from five of them. The other five had their “tubes tied,” so were sterile but still had intact ovaries. Since the monkeys wouldn’t understand the biological ramifications of surgery, and would have similar social lives, any difference between the two groups could be attributed to ovarian hormones.

During an annual corralling of the monkeys three years after surgery, the authors noted that spayed monkeys ate and drank more, and groomed and had sex less—suggesting social impairment and stress. When researchers confronted the monkeys with a black rubber snake, four out of five ovariectomized monkeys backed away and closed their eyes. (The others touched the snake and played with it.) The scientists deemed this odd behavior a “non-adaptive” response to threat and novelty, and concluded that the presence of ovarian hormones keeps female macaques calm and socially engaged. Other research on the same Oregon snow monkey troop suggests spaying impacts serotonin levels.

The benefits of spaying and neutering—peaceful behavior, no marking of furniture, no endless litters of unwanted young—are so great, though, that it’s hard to see how a dip in your dog’s mood could outweigh them in the minds of most pet owners. If research eventually shows that pets are adversely affected—and we’re a long way from that point—maybe getting pets’ tubes tied or snipped be a better option than wholesale gonad removal.

Image courtesy of Teeejayy / flickr

CATEGORIZED UNDER: Living World, Mind & Brain
MORE ABOUT: depression, hormones, mood
  • Clara

    I have been really curious about how spaying and neutering pets affects them (beyond the reproductive implications). Glad to see at least a little research looking into the question of what (if any) effect such a procedure may have.

  • Laura


    Since you’re interested, here is more information about spaying and neutering effects:

  • Grannie Cool

    I have had LOTS of animals in my 50 years as a pet owner. ALL spayed or neutered. I have NEVER seen a single animal – cat or dog – who had an issue with it. And with one female cat who was bleeding to death from her heat, she was THRILLED to have that over with. Most recently I was a bit concerned when I took in a full grown feral male who had sired at least a couple litters. (One of those litters & the mom I also took in.) He was fine with it – didn’t faze him ! I was frankly surprised, but he really doesn’t care at all. He is SO happy to be a loved housecat. I can tell you what DOES cause permanent emotional scars – declawing. I had a rescued (run-away) declawed cat & he was definately NOT OK about it. He had a LOT of emotional, & trust, issues & I’m sure it’s why he ran away from the home where they had mutilated him. I’m glad his last few years with us were happy.

  • PersonalJesus

    I love the fact that we do unspeakable things to non-consenting animals to research a topic better understood through observation of the actual subject matter. Why not research dogs and cats whose owners have had them spayed or neutered. I have met some that clearly show signs of depression after surgery, and just because an animal does not understand the abstract nature of a surgery does not mean they are not aware of the implications of it. Humans are arrogant and torture our fellow earthlings for the satisfaction of their own ego. Animal abuse is not science. We as humans are 100% dumber and meaner than we think we are.

  • Hans

    High minded moralizing falls apart when it has to deal with the dark aspects of life that science has provided help with. Claiming that this is not science is completely false and I expect deep down you know that. Animal research is not all testing perfumes and shampoo. Vaccines and medical procedures require them. Surgeons train on live pigs.

  • Gil

    3 – your suggestion would yield almost no useful data due to the lack of experimental design. For example, you’d be unable to rule out differences among the owner’s relationship with their pets, the local environments, or even feeding differences.

    And of course, the snow monkey is likely a better model than cats and dogs if you’re looking at the human implications.

  • Bronwyn

    Over the years, I’ve had 23 cats who lived with me from the time they were babies until they died. I think that I noticed a downturn in my cats’ mood after I had the older ones neutered — at least them much older ones. However, the tendency today is to neuter companion animals long before they come into sexual maturity — kittens, e.g., are neutered with then reach about 2-1/2 pounds (around 2-1/2 months old at most). These kittens have all grown up into happy, bouncy and loving cats. The only thing they think that thing between their legs is for is peeing. My dog, neutered at 3 months) also seems to be happy so long as his supply of rawhide is a big as he wants it to be.


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