Metadata Analysis of Sumatran Orangutans Population and Fruit Availability in Suaq Balimbing Research Site, South Aceh, Indonesia

Abstract

One factor that affects the distribution of orangutans in an area is fruit availability. When fruit availability is high, the energetic daily cost will be low because of the limited competition between individuals. This study aimed to observe how fruit availability affected the population structure of Sumatran Orangutans (Pongo abelii) in Suaq Balimbing. The observation was done with nest-to-nest and focal animal sampling observation methods, which analyzed using the Kruskal-Wallis test. Results show that many orangutans were spotted in the area during the years (2007-2019), with the highest number of 32 in 2010. The population structure dominancy spotted were unflanged males, mothers, juveniles, and flanged males, respectively. Adult males tend to move out from their birth area and have a comprehensive home range compared to mothers and/or females, which tend to have a small home range and stay in their birth area. Fruit availability has no significant effect on the presence of the individual of Sumatran orangutans in Suaq Balimbing. It might because Suaq Balimbing are known to have a very high fruit availability every year so that aggreration is common to happen with the orangutans.