Seed Spitting and Seed Swallowing By Wild Orang-Utans (Pongo Pygmaeus Morion) In Sabah, Malaysia

Abstract

Wild orang,utans (Pona, ptgnaeus moio) studied at the "KirabatangarOrang-utan Conse ation project", Sabah, Malaysia, are mainly frugivorous. They are regularly observed ro swallow large seeds (length longer than five rnm) ftom 37 different plant genera and to spit large seeds ftom 27 plant genera. For rkee of these genera, we compared the time to first germination, the germination success, the 507, gemination time and s€€dling mortaliry of seeds that were spat out, swallowed or left unprocessed by orang-utans. Our results show that mean time from planting ro germination was shorter and seed germimrion rate was higher for seeds swallowed or spar than for seeds collecled f.om the parent tree for two tee species (D/ac ontomzlnn dao atld Koo ensinden&on ptundt n, both sp€cies being part of the Anacardiaceae Family). For D .ddr, gemination success was better for seeds that were spat than swalowed, showing the potential inportance of seed-cleaning and seed-spitting by orang-utans for ce(ain rree species occuning within the natural orangutan habitat.