Menstruation (mammal)
Menstruation in mammals is the shedding of the uterine lining (endometrium). It occurs on a regular basis in uninseminated sexually reproductive-age females of certain mammal species.
Maternal transfer in aquatic mammals
Marine mammals are exposed to a variety of chemicals throughout their life, mostly through their diet. Once the chemicals are accumulated in the body tissues of the mammals, a portion of these chemicals in the female mammals are transferred to their offspring during gestation and lactation.