Reproductive Cycles

Sexual reproduction in most species is regulated by regular endocrine changes, cycles, in the female. There are a number of different species-specific female hormonal cycles which can regulate reproduction.

Menstrual Cycle

Human Menstrual Cycle

Human reproduction is regulated in females the menstrual cycle, a regular cyclic hormonal change which coordinate changes in the ovary and internal reproductive tract. This cycle commences at puberty and ends at menopause.

Estrus Cycle

(British spelling, oestrous) Estrus Cycle

Other species females of non-primate vertebrates, for example rats, mice, horses, pig have this form of reproductive cycle.

Polyestrous Animals - Estrous cycles throughout the year (cattle, pigs, mouse, rat).

Seasonally Polyestrous Animals - Animals that have multiple estrous cycles only during certain periods of the year (horses, sheep, goats, deer, cats).

Monestrous Animals - Animals that have one estrous cycle per year (dogs, wolves, foxes, and bear)