A male orangutan was still breastfeeding when he died at the age of nine.

Orangutans take care of their cubs longer than other mammals.
it remains a mystery how long they have been caring for their offspring, and because gorillas are home to tall tree tops, it's not easy for researchers to observe them.
, a team of scientists did not look for answers in the canopy, but in the teeth of orangutans.
calcium and vanadium are passed from the mother to the offspring through breast milk and eventually remain on the bones and teeth of the offspring.
by understanding how much calcium remains in the teeth over time, scientists speculated on how long each orangutan ate breast milk.
They found that some orangutans breast-feeding longer than previously thought, the researchers report in a May 17 article in Scientific Reports, the oldest dental samples suggest that a male orangutan was still breastfeeding when he died nearly nine years old.
but the levels do not indicate that the orangutan cubs have been breastfeeding.
, in contrast, the mother's care fluctuated a bit during the year, which is likely to mean that when fruit and other food sources are scarce, the orangutan will let the cubs breastfeed.
researchers say such longer-term growth could make orangutans even more vulnerable to rapid habitat loss, with projections suggesting their numbers could fall by half over the next decade.
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