PRIMATES, 43(3): 23%248, July 2002 237 Home Range and Ranging Pattern in the Slender Loris (Loris tardigradus lydekkerianus) SINDHURADHAKRISHNA UniversiO, of Mysore and National Institute of Advanced Studies, Bangalore, India and MEWASINGH Umversi O, of Mysore, India ABSTRACT. The home range and ranging pattern of the slender loris (Loris tardigradus lydekkerianus) was studied for 21 months in a scrub jungle in Dindigul, Tamil Nadu, south India. Sixteen individuals were observed for a total of 2261 hours. Home ranges were measured for eight adult individuals and eight juvenile and subadult individuals. Males had significantly larger home ranges than the females, and home range size increased post-weaning. The ranging patterns involved minimal female intrasexual overlap, large male intrasexual overlap and large intersexual range overlap. Key Words: Slender loris; Home range; Ranging pattern; Home range overlap; Social organization. INTRODUCTION The slender loris (Loris tardigradus, Prosimii:Lorisidae) is a nocturnal prosimian that inhab- its the dry, wet, swampy coastal and montane forests of India and Sri Lanka (RoONWAL & MOHNOT, 1977). Six subspecies - two in south India and four in Sri Lanka - are presently rec- ognized, based on geographical locations and differences in pelage and body weight (ScHULZE & MEIER, 1995). The species has been classified 'Vulnerable' by the IUCN Red Data List (IUCN, 2000); yet, for decades, as with many nocturnal prosimians, little field data was avail- able on it. The first field study on the slender loris was a 16-day population survey conducted in Sri Lanka by PETrER and HLADIK in 1970. They concluded that the slender Ioris was nocturnal, pre- dominantly insectivorous, and depended on the undergrowth for protection. Population densities were variable, with a maximal value of an animal per hectare, and an inter-individual spacing of about 100 m. Population surveys on the slender loris in southern India are reported by SARKAR et al. (1981) and SINCH et al. (1999, 2000). SINGH et al. (1999) observe that they had sighted four individuals within 50 m of each other in one of the areas they had surveyed. Three studies report home range sizes for the slender Ioris; the figures were based on obser- vations of the two subspecies found in south India and differ between the studies. The two sub- species were the malabaricus and the lydekkerianus found in the wet forests of the Western Ghat mountain ranges and the dry scrub forests of the Eastern Ghat mountain ranges respec- tively. JOHNSON(1984) calculated the home range of a male slender loris of the subspecies mal- abaricus to be 0.9 ha. In a radiotelemetric study on the same subspecies, however, KAR GUPTA & NASl~ (2001) observed much larger home ranges, varying from 2.5 ha to 34 ha. NEKAmS' (2000) study on the lydekkerianus subspecies of the slender loris reports an average adult male home range size of 3.6 ha, juvenile male home range size of 1.17 ha, and adult female home range size of 1.59 ha.