Improving survival chances for reintroduced mother and infant Sumatran orangutans

Reintroducing orangutans into the wild is the first step towards building a healthy population. Post-release the animals need to survive on there own. A new research project want to find out, how mother and infant survival rates can be improved.

From the 1st of July, we are starting a research project lead by our established orangutan veterinarian Andhani Widya Hartanti, which aims to improve the survival chances of reintroduced orangutan mothers and infants up to 70%. As more mothers and infants survive, the reintroduced population in the Bukit Tigapuluh Landscape will grow and become more viable in the long term.

In 2002, Frankfurt Zoological Society (FZS) started a comprehensive Sumatran orangutan reintroduction programme in the Bukit Tigapuluh Landscape, to establish self-sustaining populations. After more than a decade, first offspring of the reintroduced population have been born. This shows initial progress towards establishing a self-sustaining orangutan population. Nevertheless, the survival rate of infants has been only 40% recently. Most offspring die because the survival rate of their mothers is also low (50%).

A sustainable population can only be established if female orangutans are reproducing and their offspring learn to live independently in the forest. Therefore, reintroduced mother and infant orangutans still need support or human intervention in order to enhance their survival chances.

Andhani’s project is the first in Indonesia to focus on reintroduced orangutan mothers and infants. The research will concentrate on the following major issues:

The improved reintroduction technique will be summarized in a guideline for reintroducing orangutans. We will provide other orangutan reintroduction centres in Indonesia with these guidelines in order to enhance survival chances across the entire species range.

To ensure the sustainability of the project outcomes they will be integrated into the FZS’ reintroduction programme and we will share our findings with a wide range of partners including The Orangutan Project, Perth Zoo, and the local government. This project will contribute to save the Sumatran orangutan from extinction and support protection of tropical rainforest on Sumatra. The project is supported by the German Development Bank KfW.

Learn more about this project: