Both male and female dogs have sexual urges, though they come at different times throughout the year. While males are generally ready to mate whenever the opportunity presents itself, females go through an estrus cycle, otherwise known as heat. When a female dog is in heat, her sex drive is much more powerful.
About twice a year, a female dog goes into estrus, or heat. This is the only period during which she is ready and willing to accept a male suitor, as her body is ovulating and compelling her to mate. This sudden sex drive may make her anxious or aggressive, and she may urinate as a way of indicating her availability to males—the urine contains hormones that advertise her readiness. Her vulva swells and she may leak a bloody discharge.
Unlike females, male dogs are generally ready to engage in sexual behavior whenever the opportunity presents itself. Until they're neutered, males actively seek our sexual companions, marking with their urine to indicate their interest. Because of their comparatively high testosterone levels, intact male dogs may be more aggressive than neutered ones, and may compete with other intact males for dominance—or even over a potential mate. While neutering alone doesn't automatically solve behavioral issues, calming the sex drive can make your dog easier to train and control.
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