We often think that by neutering our pets we’re doing away with their sexual behaviour once and for all. And to a great extent, that is true. However, there are quite a lot of dogs who still seem “up for it” even long after their surgery… In this blog, we’re going to explore how and why!
What is dog neutering?
Neutering is a surgical procedure in which your veterinary professionals remove the key reproductive organs of your dog. In the girls, we remove the ovaries and, usually, the uterus – so no more oestrogen or progesterone, no more eggs, and no more puppies. In the boys, we just take out the testicles, leaving all the rest of the “plumbing” intact. This means no more sperm are made, and testosterone levels drop to pre-pubescent levels. This prevents dogs from being fertile and producing puppies. It can however take around 6 weeks following castration for a male dog to become infertile, however, because sperm can be stored for a short time in the remaining reproductive tract.
What makes dogs want to mate?
As a very general rule, sex drive, or libido, in dogs is hormonally triggered. In both males and females, testosterone is important, although oestrogen is also key in females. However, there are significant differences in dogs between males and females.
A female dog will usually only “stand” to be mated when she is in full oestrus (heat)
This is a hormonally driven phase, with high oestrogen giving way to high progesterone (dog hormones are a bit weird!), and something of a testosterone spike. This is why we very rarely see neutered females standing to be mated or displaying oestrus behaviour. In the female, this part of their sexual repertoire is almost entirely hormonal.
The male however is different
The drive to mount and thrust, or hump, seems to be triggered by hormones at puberty (although see below!). But once triggered, it may become a self-reinforcing behaviour. Essentially, once dogs learn how to do it, they want to carry on doing it. Presumably, because it’s “fun” or otherwise rewarding, even in the absence of high testosterone levels.
Can a castrated dog physically mate?
Yes, he can! He still has a penis, and he is still capable of getting an erection – and therefore if he wants to, he is still capable of mating. However, we need to consider when he was castrated, and how long ago.
If he was castrated relatively early, before or in the early stages of puberty, his penis will not have matured. It will be relatively juvenile, and may not be long enough to achieve normal intromission during mating. In addition, the bulbis glandis (or “knot”) will be small, and he probably won’t be able to lock. More importantly, he probably won’t have much of a desire to mate anyway. A dog who was castrated later, at or after the end of puberty, has all the “equipment” he needs, so this doesn’t apply.
However, over time, low levels of testosterone will gradually result in decline of both sexual drive and penile function, making it progressively less and less likely that the dog will develop an erection under any particular set of circumstances. Erections are normal in male puppies, and do not require high testosterone levels to occur – but are more frequent and complete with higher testosterone. So the longer your dog has been neutered, gradually the less often you will see him “putting out his lipstick”.
Can a neutered dog ejaculate?
Strictly speaking, yes. However, it will not contain sperm (once he’s past the 6 weeks needed for any leftovers to die off, anyway), and will consist solely of prostatic fluid. However, it is very uncommon for a neutered dog to do so, and over time, the prostate will shrink and produce less and less fluid, resulting in even less chance of a messy cushion!
Can neutered dogs have puppies?
In order for puppies to be produced, two dogs would have to mate, neither of whom had been neutered. If one has been neutered but not the other, a puppy will not be produced. They are however still capable of spreading sexually transmitted infections. If you are worried your female may be pregnant or have a sexually transmitted infection, please contact your local veterinary practice as soon as possible. A pregnancy scan can be used to detect puppies if you are suspicious. Bear in mind that an entire female dog kept only with a castrated male can still get pregnant – just by a visitor, not by her housemate.
Why do female dogs hump?
This is where it gets complicated!
While mounting and thrusting, for the male, and standing to be mated, for the female, are the patterned sexual responses for each gender, the other behaviours – especially mounting and humping – are still available. We can consider these to be displaced behavioural repertoires – behaviours that serve a different function from what we conventionally expect.
For example, humping is a common response to excitement or overstimulation, and is seen in puppies and adults, even when there is no sexual stimulus involved. There may also be communication roles, perhaps in exerting dominance – although that’s a long way from being proven. In these cases, it is better to consider the humping as a behavioural quirk, rather than a sexual act.
Is it a problem if neutered dogs hump things or try to mate?
Not usually, although trying to mate can increase the risk of sexually transmitted infections. In most cases, though, the urge to do so will decline with time. If it doesn’t, it’s worth double checking with your vets to make sure that the dog was neutered properly – mistakes do happen, albeit very, very rarely, and there are tests that we can run. After that, seek advice from a behaviourist, as it’s probably a behavioural, rather than a sexual, issue!
Further reading:
Discussion
I have an 18 month old male. I got him 6 months ago and was told he was neutered at 6 months. He is a medium sized mongrel. From the looks of things I would agree he has been neutered however he is constantly all over my female who is in heat. She is letting him too. I am now keeping them separated as I’m worried about potential damage to my female but everytime he saw her he was jumping on her and entering. Is this normal?
It can be, but I’d suggest getting a vet check anyway; there is a chance he’s a cryptorchid (has an undescended testicle still producing testosterone, so he doesn’t “realise” he’s been neutered).
Otherwise, it’s more likely to be a behavioural issue.