Arrested Development and Rape in Orangutans

A general overview of the trait of arrested development and its result, rape, in orangutan populations.

The paper investigates a unique characteristic found within the development of male orangutans whereby the reaching of complete maturity and adulthood among a portion of orangutan males, both in the wild and captivity, is held off and slowed down by natural means. The paper explains how developmentally arrested orangutans remain subadults, smaller and less physically mature than their fully grown adult male counterparts. It explores a number of studies which have been conducted to attempt to determine the reasons and causes for what is often called bimaturism. The paper shows that because of the lower status of subadult males, female orangutans prefer to copulate with dominant, fully mature males. Often, in order to receive sexual gratification, subadult orangutans force unwilling females to have sex and the act of rape is extremely common among orangutans. The paper shows how a number of studies have been conducted in order to better understand the reasons for bimaturism and the effects of the trait on orangutan populations and the species as a whole.
“Because of their solitary, illusive nature, it is often difficult to observe orangutans in the wild. It was previously believed that orangutan males reached puberty sometime between the ages of seven and nine. Researchers thought that developing males would spend a few years in an intermediate stage, before becoming a full grown adult sometime between twelve and fourteen. However, after populations were established in zoos, scientists noted that subadults would remain in the arrested development stage as long as a dominant male was present. When the fully mature male was removed, the subadult males would physically develop the traits of dominant males, most notably the wide cheek pads, and long, brightly colored hair.”