When Do Male Dogs Become Sexually Active?

At about six to nine months of age. However, some males may mature as early as four months, while others may not be ready until they are over a year old.

Signs that your male dog is sexually mature include:

- Trying to mount other dogs or people.

- Increased sniffing of other dogs' rear ends.

- Producing sperm in his semen.

- Urinating to mark territory.

- Trying to escape to find a mate.

- Increased aggression, especially toward other male dogs.

If you are not planning on breeding your dog, it is important to have him neutered before he becomes sexually mature. Neutering will help to prevent unwanted pregnancy, aggression, and other behavioral problems.