Do polar bears go into heat?

No, polar bears do not go into heat. Polar bears are seasonally polyestrous, which means that they come into estrus (a state of sexual receptivity) once a year, typically during the late winter or early spring. During this time, female polar bears will mate with multiple males, and the fertilized eggs will implant in the uterus and begin to develop. The gestation period for polar bears is approximately eight months, and cubs are typically born in the late autumn or early winter.