By Austa Somvichian-Clausen for National Geographic
The world’s largest tree climbers, orangutans now have another superlative to their name: They nurse their young longer than any other primate, a new study says.
Surprising new research has revealed that the colorful great apes suckle for up to eight years, and in some cases longer.
Little is known about when the shaggy great apes wean in the wild, in part because they’re so challenging to study—they spend most of their time aloft and out of sight. But knowing when juveniles strike out on their own is important for conservationists working to save them.
For the new research, Tanya Smith and colleagues developed a creative method for tracking how long orangutans nurse: Analyzing the levels of barium, a trace element, in young orangutans’ teeth. Because barium absorbs into young orangutans’ skeletons from their mother’s milk, it can reveal how long an orangutan had been nursing.
“This paper represents an exciting new method of determining weaning age from the teeth of wild primates,” says biological anthropologist Cheryl Knott, director of the Gunung Palang Orangutan Project in Indonesia’s Gunung Palung National Park.
This excerpt from a news article appeared in and is courtesy of National Geographic and can be read in its entirety here.