More recently Sri Suci Utami of Utrecht University in the Netherlands has shown that arrested adolescents fathered approximately half of the orangutan babies at her Sumatran study site.

• 最近荷兰乌特列兹大学的乌塔米发表报告，她在苏门答腊研究一群红毛猩猩，新生儿中约有一半是发育迟滞雄性下的种。