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Orangutans
Sumatran orangutans have a baby once every 9 years
- Female Sumatran orangutans have a baby once every 9 years or so (every 9.2 to 9.3 years).
- This is the longest interbirth interval for any great ape species. This includes being longer than Bornean orangutans by a couple of years.
- That interval between babies is shortened if the baby dies.
- The low fruit availability may be the cause of the long interval between births. The mother has to delay the weaning of her baby until it is old enough to forage alone.
- Unlike a chimp or human, an orangutan mum can’t cope with looking after several kids at once. Feeding and caring for several offspring at once would take up too much of her resources.
- Infant mortality is very low in orangutans compared to other apes. That might be due to their solitary nature (parasites don’t spread between them) or just a side effect of their longevity.
- Females can continue having babies until they are at least 41, possibly until they are 50 years old.
- 3 year old orangutans can move around the tree without mum’s help.
- 3 year olds are competent at building nests, but still share a nest with their mum until they are 7 years old.
- They will be weaned when they are 8 years old.
- Infant mortality in Sumatran orangutans is 7 to 17%.
Orangutan mother and child form a very strong bond
An orangutan mum has up to eight years to prepare her child for adulthood.
