Q:

When do dogs start to menstruate?

A:

Like most mammals, female dogs undergo estrus, or a heat cycle, rather than experiencing menstruation. This usually occurs for the first time between the first nine and 12 months of the dog's life and reoccurs either biannually or annually from that point.

The first stage of the heat cycle is called proestrus. This usually lasts nine days, although this can vary by breed. In proestrus, the dog's vulva becomes swollen and the vagina emits a reddish-brown discharge. Estrogen levels rise, although mating does not occur yet. The second stage, estrus, follows and is typified by flirtatious behavior around male dogs and the ability to successfully become pregnant once ovulation occurs. Diestrus is the third stage and follows the same pattern whether the dog is pregnant or not. Anestrus, the final stage, lasts the longest and is the dog's way of preparing for another cycle.

Learn More
Sources:

Related Questions

  • Q:

    How much do dogs sleep?

    A:

    On average, dogs sleep about 14 hours a day. Larger dogs, such as Saint Bernards, mastiffs and Newfoundlands, sleep as much as 18 hours a day. Puppies, who expend energy growing and learning, sleep for 18 to 20 hours per day.

    Full Answer >
    Filed Under:
  • Q:

    Why do dogs howl?

    A:

    Dogs howl to gain attention, announce their presence, send a warning, or to express anxiety. Howling is a way that dogs and wolves to communicate with one another over long distances.

    Full Answer >
    Filed Under:
  • Q:

    What do dogs eat?

    A:

    Although their ancestors were primarily carnivores, dogs today are omnivores. They eat a variety of foods, including meat, vegetables, fruits, carbohydrates and dog food.

    Full Answer >
    Filed Under:
  • Q:

    Are hydrangeas poisonous to dogs?

    A:

    According to the American Society for the Prevention of Cruelty to Animals (ASPCA), certain parts of hydrangea plants are particularly toxic to dogs. The buds, flowers and leaves are highly toxic and, in extreme cases, can prove fatal.

    Full Answer >
    Filed Under:

Explore