Orangutans are vital seed dispersers, according to a new study.


Seeds are spread by the great apes as they travel through forests – male orangutans have larger home ranges than females and therefore distribute the seeds more widely.

“We found seeds in 73 per cent of orangutan faeces, with 828 seeds found in one poo!” says lead author Dr Esther Tarzisz. “Seeds varied in size from a few millimetres to two and a half centimetres.”

Both wild and captive orangutans were studied, the former in the Sabangau Forest in Borneo and the latter at Taronga and Perth Zoos in Australia.

In addition to helping the seeds disperse from the parent plant, the study showed that orangutans handling of the seeds encouraged them to germinate.

“For four out of five species studied, seeds that were either spat out or defecated by orangutans showed either germination success and/or quicker germination, compared with seeds that had not,” says Tarzisz.

Researchers believe declining orangutan populations are likely to impact the diversity of forests.

Bornean orangutans are one of three orangutan species, all of which are Critically Endangered due to habitat loss and degradation, and hunting.

“Any loss of orangutans from forests will influence the seed dispersal process, particularly for those larger seeds that smaller forest animals avoid,” says Borneo Nature Foundation’s Dr Mark Harrison.

Read the full papers in Biological Journal of the Linnean Society and Conservation Physiology.


Main image: Scientists have been studying the contents of orangutan faeces. © Pau Brugues Sintes / Borneo Nature Foundation


Megan ShersbyNaturalist, writer and content creator