What is the term for the reproductive cycle in female animals that is initiated by hormonal changes, including heat?

The term for the reproductive cycle in female animals that is initiated by hormonal changes, including heat, is known as the estrous cycle. This cycle encompasses the various phases of reproductive activity in females, including proestrus, estrus (heat), metestrus, and anestrus.

During the estrous cycle, hormonal fluctuations govern the development of ovarian follicles, the maturation of eggs, and the timing of heat, which is the period when the female is receptive to mating. This cycle varies among different species, both in length and specific characteristics, but the key feature is that it is hormonally regulated and is intrinsically linked to fertility and mating behaviors.

The menstrual cycle, on the other hand, specifically refers to the reproductive cycle in some primates, such as humans, and involves the shedding of the uterine lining if fertilization does not occur. The follicular and ovulatory cycles are components of the broader estrous cycle, with the follicular phase dealing with follicle development and the ovulatory phase referring to the release of an egg from the ovary. Understanding the estrous cycle is essential for animal reproduction and breeding programs.