The age of puberty not only varies between species, but also among individuals within the same species. Puberty is brought on by hormone secretions, primarily of estrogen. F. Estrus and the estrous cycle 1. The first estrous cycle begins at puberty and is the interval between two estrous periods while the animal is not pregnant. Non-pregnant females normally express both inward and outward signs of heat throughout the year.
Estrous cycles stop after conception.
Have students identify all organs listed. Free End of Penis 2. Cowper's Gland 2. Vas deferens 5. Vas deferens 6.