Orangutan Mothers Traveled Farther and Fed Less During Offspring Play Encounters, Study Finds

Female orangutans, which are generally solitary, were observed ranging farther in the days around encounters between similarly aged offspring, researchers reported. Researchers analyzed 15 years of data on 31 wild Bornean orangutan mother-offspring pairs, covering roughly 30,000 hours of observations on location, companions and activities.

Mothers with similarly aged offspring spent a disproportionately high amount of time in the same area.

Young orangutans played more often during these encounters, and play occurred more frequently when the mothers were closely related. The distance traveled by the apes rose in the days before and after these meetings as mothers entered neighboring territories and returned. Meet-ups took place irrespective of local fruit availability.

The added travel reduced the time mothers spent feeding. Odd Jacobson at the Max Planck Institute of Animal Behavior and colleagues concluded that the mothers adjust ranging behavior to increase offspring access to social play. Adriano Lameira at the University of Warwick noted that male orangutans use long calls to signal travel direction a day ahead, but females are not thought to use long-distance calls for coordination.

He suggested the encounters rely on what the animals can see and hear from the trees along with their local knowledge of resources. The study is available as a preprint on bioRxiv with DOI 10.64898/2026.06.20.733430. Zarin Machanda at Tufts University said the data indicate mothers may choose to socialize their young with peers rather than only with themselves.