Mature bulls are central to male social groups
Incident in Pilanesberg National park, South Africa
One event in Pilanesberg National Park, South Africa has helped demonstrate the importance of mature bulls in the development of adolescent males.
All adolescent elephants go through a state of musth.Musth is a state of intensified testosterone levels, as well as increased sexual and aggressive behavior in male elephants. Swollen and secreting temporal glands, urine dribbling, and aggressive activities are some of the main characteristics of this state. Normally, musth first occurs in males between 25-30 years of age, but the duration of musth increases with age.
When young orphaned males younger than 10 years of age were introduced to the park, they started breeding by 18 years of age and entered musth shortly after. These males entered musth 10 years younger than expected, and started to act aggressively towards the rhinoceros, killing as many as 40 rhinoceros.
At a separate event in Kenya, when bulls were introduced to a population of elephants, the young males were less likely to be in musth with the older bull’s presence. It is hypothesized that young males were forced out of their violent musth state by aggressive interaction with an older bull. The change in behavior when an older bull is present is a strategy that can increase immediate survival, and long-term reproductive success of the young elephants.
This same idea was tested on Pilanesberg’s elephants. 6 mature bulls were introduced to this population, and there was an obvious change in behavior. The young elephant’s musth lasted a shorter amount of time, it was delayed, and rhinoceros were not killed (Slotow et al., 2000). By aggressively interacting with the young elephants, bulls were able to promote normal development in adolescent males. This provides evidence that bulls play an equally important part in sustaining the development of male social groups just as matriarchs do.