Paper short abstract:

Orangutan is one of the extant species of hominidae with chimpanzee, gorilla and human. There is less report physical and psychological troubles related to pregnancy and childbirth in wild Orangutan while the troubles are very common in the captivity and human-reared individuals.

Paper long abstract:

Orangutan (Pongo sp.) is only one extant great apes living in Asia while the other great apes; Chimpanzee (Pan sp.) and Gorilla (Gorilla sp.) living in Africa. Orangutan is the only solitary species in extant diurnal primates and its reproductive speed is very slow; it births only one offspring every 6-9 years and age at first birth is average 15 years old in the wild. However, we found that human-reared (rehabilitant) orangutans, which lost their own mother by poaching and reared by human then released in the wild as conservation projects, born every 6 years and age at first birth was average 11.6 years old, shorter and younger than wild one. Additionally in the wild, mothers of orangutan are hardly dead or loss of health related to pregnancy and childbirth while rehabilitant mothers frequently were dead or loss of health during or after birth. In the captivity (zoos), similar high risk of health related to childbirth was reported with frequent child neglect. This paper reviews troubles related to pregnancy and childbirth in the captivity and human-reared orangutans compared with other great apes. Then I discuss what factors influence on pregnancy and childbirth in great apes; especially focus on growing environment of mother, rather than genetic or innate differences. This paper will contribute how growing environment of mother effects on pregnancy and childbirth over Hominidae, included human.