Little Bella just arrived home after receiving her second vaccines. The first vaccination had been a delight, and Bella received a million cuddles and treats! She even liked the vets then, but this time there was a discussion about spaying.

The vet informed Bella’s mum how the surgical procedure would significantly reduce the risk of breast cancer and pyometra (a uterine infection that can progress to septicaemia and become life-threatening). This sounded important, but would she need to be at the vets for an entire day without her mum? And how would she change after her female reproductive organs had been removed? There was a lot to consider…

The story was a little different with Buddy. Other male dogs suddenly started feeling intimidating and he felt anxious around them, barking and growling non-stop. It was also frustrating to stay inside when there was so much going on outside. Buddy started scratching the door, jumping and circling; he just felt very irritable and unsettled in the house.

His dad was worried about this sudden change in behaviour and took him to the vets, who mentioned castration could help him feel more at ease. But Buddy’s dad loved him and did not want to change his personality, was he being selfish and not accepting his dog for who he was?

Although the two dog parents had different reasons to consider neutering their dogs, they both asked the same question:

Will neutering my dog change their personality or behaviour?

Before answering this question, it is important to understand what neutering means and what changes occur internally when a female dog is spayed, or a male dog is castrated.

Neutering refers to the surgical removal of organs responsible for the production of sexual hormones; ovaries in females and testicles in males. In females, the uterus is often removed too. With time, the level of sexual hormones decreases and becomes very low and stable. 

Sexual hormones exist to guarantee survival of a species through reproduction. They are, therefore, responsible for physical changes that allow dogs to breed. But they also introduce psychological changes that influence dogs’ behaviour to increase the chances of mating. 

The differences between personality and behaviour

However, personality is much more complex than that. Although a dog’s behaviours can be influenced by their sexual cycles, sexual-driven behaviours are just a fraction of dog’s interactions with other dogs and humans. It also does not define their personality.

There are many other influencing factors such as genetics, social interactions, training, and past experiences. Furthermore, a lot of these behaviours are learned, and what can start as a sexual behaviour may continue after a dog has been neutered, simply because they have learned to do so.

In fact, when a dog is a companion and not used for breeding, a constant high level of sexual hormones that is unnecessary for that dog’s lifestyle may lead to unwanted behaviours such as;

  • False pregnancies
  • Aggression towards humans and other dogs
  • Self-trauma to the genital external organs
  • Frequent urination on the walls
  • Anxiety

Can neutering eliminate unwanted behaviours?

As discussed above, behaviours that were sexually stimulated at the start may become learned and independent from hormonal influence. In these cases, neutering may help by removing that constant hormonal stimulus, but the behaviour is unlikely to disappear without training. Behaviours that are solely stimulated by hormones, have only started when the dog reached sexual maturity and have been present for a short period of time have higher chances of disappearing with neutering alone.

Please note, it is extremely challenging (if not impossible) to determine if a dog’s behaviour is hormonal driven before neutering. Testosterone increases a dog’s sense of “self-confidence” and risk-taking. For this reason, in some cases of fear-induced aggression, castration may actually worsen the problem. If you are unsure if this is the case, consult with your vet and consider contacting a trusted veterinary behaviourist before neutering your dog.

Take-home points:

  • Personality is a very complex subject and is not defined by the level of sexual hormones, which are just one of the many factors influencing dogs’ behaviour.
  • The role of sexual hormones is to drive reproduction. A companion dog does not need to be wary of other dogs, show dominance or guard toys, and these unnecessary hormonal-driven behaviours may get in the way of dogs’ well-being.
  • Sexual-driven, unwanted behaviours may become learned and need training alongside neutering to be modified.
  • Neutering has been associated with numerous health-benefits and may be in your dog’s best interest.

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