For many of us, the word “puberty” will often invoke memories of that awkward teenage phase when your body is changing and you’re trying to navigate a new world of school exams and peer pressure. But what does puberty look like in our dogs? And at what age do our dogs start going through puberty? This article will explore these questions about canine puberty and more.

What is puberty?

Let’s start with a scientific explanation of what puberty in dogs actually is. Puberty is generally defined as the age at which a dog becomes old enough to reproduce. As a dog nears the age of puberty, a part of his or her brain, called the hypothalamus, begins to release a hormone called gonadotropin-releasing hormone (GnRH). Puberty begins once GnRH is released in large enough quantities to promote the development of the dog’s reproductive organs and the release of hormones such as oestrogen and testosterone.

How do I know my dog has reached puberty?

Female dogs

In female dogs, puberty is generally marked by their first “season” or “heat”. This refers to the oestrus stage of a dog’s reproductive cycle. This is the stage when female dogs are able to become pregnant (if they have mated with a male dog). Signs that a dog is in oestrus include swelling of the vulva, bloody discharge from the vulva, frequent urination and an increased interest from other dogs. The oestrus phase lasts on average for a period of 1.5-2 weeks.

Male dogs

In male dogs the most common sign of puberty is mounting or humping behaviour. You may see your dog mount toys, furniture, other dogs and sometimes even humans! This may feel embarrassing but it is very common. They may also exhibit roaming behaviour where they will go to great lengths to sniff out a female dog in heat. 

Behaviour changes

Behaviour changes can occur in both male and female dogs as they reach puberty. For example they may become more bold and excitable or more reserved and clingy than usual. Behaviour changes seen are usually an exaggeration of their existing personalities.

Much like when us humans reach our teenage years, many dogs also become more rebellious as they reach adolescence. For example, they might try to engage in behaviours they’ve previously been told not to do, or they might ignore commands they’ve previously obeyed. You may also notice a change in their behaviour when interacting with other dogs. For example some dogs become more competitive and domineering. Whereas others will become more submissive in their interactions. 

This VetHelpDirect article looks at a study which shows that dog adolescent behaviour mirrors that of human adolescent behaviour and it delves further into the behaviour changes we can expect to see around this time in a dog’s life.

At what age does a dog reach puberty?

The age of puberty varies greatly from dog to dog. Male dogs can reach puberty anywhere between 5-12 months of age and females between 6-24 months.

Why does the age of puberty vary so much?

The age of puberty tends to vary because smaller dogs tend to develop more quickly than larger dogs, and this means they reach puberty quicker. Simple right? Well just to make things a bit more confusing, although smaller dogs develop more quickly than larger dogs in their first few years, in general they tend to age more slowly and have longer lifespans than larger dogs. 

The age of puberty can also vary between breeds – so just because one breed is smaller than another breed – it doesn’t necessarily mean they will reach puberty first. Genes commonly carried by different breeds can play a role in rate of development and onset of puberty. 

However the general rule to remember is that the smaller the dog, the earlier they will reach puberty! Smaller breeds generally enter puberty around 6 months of age, and larger breeds between 1-2 years of age. 

So why do some dogs reach puberty so early? Well, canine development occurs much more quickly in the first two years of a dog’s life compared to the rest of its years. It has been estimated that in the first two years of a dog’s life, one dog year is equivalent to about 10.5 human years. However, from the age of 3 years onwards, one dog year is more equivalent to 4 human years (you may have heard the common myth that one dog year equals 7 human years – this is in fact inaccurate!) Again, these estimates will vary depending on the breed and size of the dog. 

What is delayed puberty?

Some dogs fail to show signs of puberty or they fail to demonstrate fertility after the expected age. Potential causes of this include:

  • Poor nutrition
  • Excessive physical activity
  • Silent heat (female dogs only)
  • Lack of exposure to other cycling females (female dogs only)
  • Hormonal suppression as a result of certain medications or infections
  • Autoimmune disease
  • Chromosomal abnormality
  • Abnormality of the reproductive organs

However, in most cases, dogs presented at the vets for delayed puberty are normal and will show signs of puberty a short time after. It is advisable to wait at least two years before undertaking more invasive examinations to investigate delayed puberty in a female dog and at least one year in a male dog. 

Some female dogs experience a silent heat, this is when they do pass through the oestrus phase, but they fail to show external signs such as bleeding from the vulva. 

Possible methods of diagnosing the cause of delayed puberty include performing genital examinations, analysing semen (for male dogs), testing hormone levels, and karyotyping (performing a complete count of the patients chromosomes). You should speak to your veterinarian about which diagnostics they would recommend for your dog. 

Treatment will depend on the underlying cause of the condition. 


Puberty in dogs is often recognised by the first oestrus phase in female dogs, or by demonstration of mounting behaviour in male dogs. The age of puberty varies greatly from dog to dog, smaller breeds generally enter puberty around 6 months of age, and larger breeds between 1-2 years of age. Behaviourally, puberty in dogs can look very similar to human adolescent behaviour. 

Further reading: