Three decades of Philippine nonhuman primate studies: research gaps and opportunities for Philippine primatology.

The Philippines is considered a megadiverse country. However, there are few published studies on its nonhuman primate (NHP) species (Carlito syrichta, Macaca fascicularis, and Nycticebus menagensis). Understanding the nature and extent of existing NHP research in the Philippines would help us to determine research gaps and opportunities. Thus, studies on NHPs of Philippine origin were retrieved from online databases including Google Scholar, ResearchGate, Primate Lit, the Integrated Taxonomic Information System (ITIS), and relevant authors. Of a total of 107 studies on Philippine NHP from 1989 to 2019, most focused on Philippine long-tailed macaque (52.78%), and Philippine tarsier (42.59%), with far fewer on Philippine slow loris (4.63%). Fewer studies were based on fieldwork (26.17%); more were based on research on captive animals or that undertaken in the laboratory (34.58%), or used only existing specimens or data (33.64%). Studies on wild NHPs were mostly conducted in Bohol Island. In terms of the type of research, studies on diseases (38.60%) were the most prevalent for macaques; ecological studies (23.91%) for tarsiers; evolutionary, taxonomic, and systematic studies (40%), and ecological and natural history studies (40%) for lorises. Philippine researchers and collaborations with foreign researchers contributed fewer studies (43.93%) than foreign-only researchers (56.07%). In conclusion, although research on Philippine NHPs is increasing, there is a bias with regards to the species studied, the type of research, and study location. Conservation-driven studies are also lacking. These gaps offer opportunities for further research to identify threats to the survival of NHPs in the Philippines, and for the development of plans and effective strategies for their conservation.