Britannica Sources used in this answer

At what age do dogs usually reach sexual maturity?

Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.

A Labradoodle dog runs energetically through grass with a stick in its mouth, ears flopping and tail raised. — dog A Labradoodle is a cross between a Labrador Retriever and a Poodle, a mix intended to incorporate the Poodle's intelligence and low-shedding coat with a Lab's energy and determination.

Dogs generally reach sexual maturity between 6 months and 1 year of age, though there is significant variation based on breed size. Small breeds typically mature faster, while larger breeds often reach sexual maturity later.12

For females, the first heat cycle can occur anywhere from 6 to 18 months of age, with 8 to 9 months being the norm for many dogs. Large-breed females may not experience their first cycle until after 1 year of age. Male dogs are typically fertile from the onset of sexual adolescence, usually after 6 months, though larger-breed males may take a few months longer to reach full maturity.12

It is important to note that while dogs are sexually mature by this age, they are not considered socially mature until they are approximately 2 years old.1