Results of a nationwide census of the long-tailed macaque (Macaca fascicularis) population of Singapore

• Main Authors: Riley, Crystal M., Jayasri, Srikantan L., Gumert, Michael David
• Other Authors: School of Humanities and Social Sciences
• Format: Article
• Language: English
• Published: 2015
• Subjects: Singapore; Long-tailed macaques; Synanthropy; Population census
• Online Access: https://hdl.handle.net/10356/81190; http://hdl.handle.net/10220/39190; http://lkcnhm.nus.edu.sg/nus/index.php/63
• Institution: Nanyang Technological University

Long-tailed macaques (Macaca fascicularis) are known for their ability to thrive in a wide variety of habitats, including urban areas. Singapore is an island city-state that has experienced rapid deforestation and urbanisation over the past several decades. These processes have led to the loss of most of Singapore’s large mammalian species, but long-tailed macaques still live on the island. We conducted a census of long-tailed macaques between 2011 and 2012 to determine the current status of Singapore’s macaque population. We surveyed forest edges, counted groups, and classified the age and sex of all individuals. We estimated the macaque population to be 1810–2166 individuals distributed among 92 groups, and a density averaging 6.86 individuals per km2 (range: 0.89–33.63 across six zones) in areas with macaques. We found no evidence of overpopulation. Rather, the population characteristics mirror those of non-provisioned, wild long-tailed macaque populations. However, the interpretation of our results is limited by the fact that we did not have access to records documenting the number of macaques culled in Singapore before and during this census. Without accurate culling records, it is not possible to assess what shapes the current population structure, and thus research on the past effects of culling is needed.