Using Hormone Field Kits to Improve Our Understanding of Ovarian Activity in Free-Living Elephants (Loxodonta africana), North America, South Africa, Tanzania Over one third of African savannah (Loxodonta africana) and one tenth of Asian (Elephas maximus) elephants in North American zoos that are hormonally monitored exhibit irregular estrous cycles or no ovarian activity. What causes this problem is not known, but it appears to be related to the age and social rank of the female. Although it is assumed that free-ranging elephants are always pregnant, lactating or cycling, hormone characterizations of estrous cycle dynamics have only been conducted on captive elephants. It is not known whether acyclicity occurs in the wild because it has never been scientifically investigated. Birth and conception rates of elephants in many free-ranging populations suggest that age and precipitation affect reproductive success. If progestin concentrations decline during the dry season or as females reach matriarchal status, it could be functionally similar to the ovarian inactivity measured in captive elephants year round.

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