In those mammals which are seasonal breeder, the females are receptive only once a year; the cycle is termed as:

Estrous cycle comprises physiologic changes that are induced by reproductive hormones in most mammalian females. Humans undergo a menstrual cycle instead. The Humans and the Estrus cycle Mammals share pretty much the same Hypothalamic and pitutary ovary and endometrial axis but there are impoant differences as well. Estrus species vary significantly in the detailed functioning. One difference is that animals that have estrous cycles reabsorb the endometrium if conception does not occur during that cycle. Animals that have menstrual cycles shed the endometrium through menstruation instead. Another difference is sexual activity where species with estrous cycles are generally only sexually active during the estrus phase of their cycle also referred to as being "in heat." In contrast, females with menstrual cycles can be sexually active at any time in their cycle.