Infant development in the slender loris (Loris lydekkerianus lydekkerianus)

Abstract

In this article we present data on infant development in wild slender loris, a nocturnal primate species. The behavioural ecology of the grey slender loris Loris lydekkerianus lydekkerianus, a nocturnal strepsirrhine, was studied for 21 months (October 1997-June 1999) in a scrub jungle in Dindigul, south India. A total of 22,834 scans were collected during 2656 h of observation on identified and unidentified lorises using instantaneous point and ad libitum sampling methods. Developmental schedules were observed for twelve individuals born during the course of the study period. A greater number of twin births were observed than singleton births and more isosexuals than heterosexuals. Infants were parked at the age of 3 weeks and weaned by 5 months of age. Individuals showed significant developmental differences in their activity schedules. Females appeared to reach sexual maturity by 10 months of age. Social interactions with related conspecifics decreased with age and adult slender lorises did not show differences in social time spent with related and non-related conspecifics.