Reproduction

Mother and baby elephant image taken from http://commons.wikimedia.org/wiki/File:Asian_Elephant_and_Baby.JPG

How do Asian elephants reproduce?

Asian elephants reproduce sexually. They exhibit “polygynous mating” in which females choose which males they want to mate with and the males compete for the females.

Anatomy & Physiology of Reproduction

Females

There are chemical signals that mediate sexual interactions and communication both between and within the sexes during reproduction. Females have an oestrous cycle also known as an estrous cycle, which is similar to a menstrual cycle in humans and it lasts about 22 days. Copulation can only occur on the first day of estrus; therefore, a sexually active status in females is limited. Asian elephant females release certain chemicals in their urine prior to ovulation, which is an indication of their reproductive status.

elephant feeding image taken from http://commons.wikimedia.org/wiki/File:Elephant_breastfeading.jpg

Males

Asian elephant males also release sex hormones. Starting at the age of 20, Asian elephant males come into a phase annually called “musth.” During musth, males have heightened levels of testosterone, resulting in very aggressive behavior. During this period, which may last up to 60 days, males try to find females that are sexually active. Most of the elephant’s food and fat reserves get burned and used for energy. The temporal gland between their eyes and ears swell and discharge a viscous, aromatic secretion. In addition, the urine they excrete contain soluble pheromones which are chemicals that signal both female and male elephants of their musth state.

Life History

Gestation typically lasts anywhere from 18-22 months. Females give birth every three to four years under good conditions, but this can be much longer if conditions are poor. Newborns can walk soon after they are born and typically weigh about 100 kg. Infants eat grass and their mother’s dung which breaks down cellulose but they continue to nurse till they are about 18 months old. Mother’s look after their calves for several years and become sexually mature at about 14 years of age. Males also mature at this age but the key difference is that females stay with their female relatives their whole lives; whereas, males leave their herds after they are sexually mature.