Behavior and Food of Reintroduced Bornean Orangutan ( Pongo pygmaeus wurmbii ) at Feeding Site and Forest Area in Lamandau Wildlife Sanctuary

Abstract

The Bornean orangutan (Pongo pygameus wurmbii) is a Critically Endangered large Asian primate. Reintroduction had been implemented to recover their population in the wild. The research was conducted in February-April 2021 at Lamandau Wildlife Sanctuary, aimed to identify behavior differences at the feeding site and forest, composition and preferences for additional and natural feed by following 6 reintroduced Bornean orangutans. The total observation duration was 219 hours using focal animal sampling and instantaneous records. Feed preferences data analysis using Neu index then categorized as rank, and Jacobs's index then categorized as highly preferred, preferred, less preferred, not preferred, and uncategorized. The additional feed had little effect on the reintroduced orangutan's arrival to the feeding location, hence their stay in the forest was longer than at the feeding site. The highest daily activities by age class and gender were foraging (32%) by adult female, resting (44%) by adolescent female, and moving (25%) by adult male and female. The part of plant that consumed were fruit (51%), young leaves 25%, and other parts of vegetation (15%). The first rank additional feed preference is banana (Musa sp.), and second is papaya (Carica papaya). The natural feed preferences of highly preferred were papung (Sandoricum ermarginatum, Di 0.73) and kumpang darah (Knema conferta, Di 0.66). Other categories are 9 species preferred, 7 species less preferred, 16 species not preferred, and 8 species uncategorized.