Family units comprise related adult cows and their immature offspring. The family unit is led by the oldest, and usually largest, female called the matriarch. As bulls reach 12-15 years of age, they often leave their natal group to wander alone. Bulls temporarily rejoin female-centered units, especially when females are sexually receptive. During musth, a bull's testosterone level in the blood skyrockets, and he becomes dangerously aggressive, unpredictable and highly competitive with other bulls for females.
Females appear to prefer males in musth for mating.
Woodland Park Zoo's four female Asian elephants and one female African elephant can be seen at the Elephant Forest exhibit located in the Tropical Asia bioclimatic zone. The elephants have use of a large area that includes a paddock, bathing pool and barn. On cold or wet days, visitors can expect to find the elephants in their comfortable barn. The Asian elephant is an endangered species. As an example, the zoo is working in cooperation with the Oregon Zoo, Portland, Oregon, in attempts to artificially inseminate Asian elephants.