Oryx Vd 33 No 1 January 1999 Status survey of slender loris Loris tardigradus lydekkerianus in Dindigul, Tamil Nadu, India Mewa Singh, Donald G. Lindburg, A. Udhayan, M. Anand Kumar and H. N. Kumara Abstract A survey of the slender loris Loris tardi- Body measurements taken on sample animals revealed gradus, a Vulnerable primate, was carried out in the that the population belongs to the subspecies L. t. Dindigul Forests of Tamil Nadu, India, in 1996 in order lydekkerianus. Conservation measures for the species to assess prevalence. Lorises were found in high in this region include additional surveys and evalu- densities in the open Euphorbia scrub forests and in ation of prospects for establishing a slender loris sanc- crop lands nearby. Although most often seen in tuary. bushes and Acacia trees, the species uses a wide variety of vegetation and substrates. Individuals Keywords Loris conservation, loris habitat, loris mor- were found mostly at an altitude of 300-500 m. phological traits, loris prevalence, slender loris. Introduction doubtful whether the type locations of these specimens were correctly reported. The only report available The slender loris Loris tardigradus Linnaeus, 1758 in- regarding the distribution of lorises in coastal Karna- habits southern India and Sri Lanka. The Indian taka and the Mysore plateau (Devaraj Sarkar et al., population is distributed approximately from the 1981) mentions neither anything about subspecies nor Tapti and Godavari Rivers southward to the tip of the indicates the number of animals sighted or relative subcontinent. Six different subspecies have been densities in different areas. recognized throughout its range (Ellerman & Morrison- Scott, 1951). In India, L. t. malabaricus Wroughton, 1917 Because the slender loris is classified as Vulnerable inhabits the wet forests of the Western Ghats, and L. t. (IUCN, 1996), it is essential to obtain as much infor- lydekkerianus Cabrera, 1908 is found in the relatively dry mation as possible on its status in wild habitats. The shrub jungles of the Eastern Ghats (Roonwal & present survey was undertaken as a first step in assess- Mohnot, 1977; Schulze and Meier, 1995; Fig. 1). Four ing the status of an Eastern Ghats population. subspecies are reported for Sri Lanka (Hill, 1953; Petter & Hladik, 1970), but according to Jenkins (1987), Location and physical features of the existing classifications of lorises cannot be said to be surveyed area final. Schulze & Meier (1995) confirmed, after breeding slender lorises in captivity for several years, that Our survey was conducted in the eastern part of subspecific differentiation is often difficult as a result of Dindigul District, State of Tamil Nadu, southern India, large inter-individual variations in colour and size in the Ayyalur, Sirumalai, Nattam and Alagar Hills within subspecies. forest ranges, and the Ayyalur Interface Forestry Div- ision (Fig. 2). All fall roughly between 77°54'-78°17'E No systematic surveys of the distribution of the two and 10°4'-10°40'N. The altitude in this region ranges Indian subspecies have been conducted. Existing infor- from about 250 m a.s.l. in the plains to about 1350 m mation is based on only a few sample specimens a.s.l. at Sirumalai Hill. The climate is generally hot and collected over the past 100 years or so. It is even dry, and most of the area is drought prone. Rainfall is received primarily from the north-east monsoon and is Mewa Singh, A. Udhayan, M. Anand Kumar and H. N. Kumara concentrated during the months of September to Psychology Department, University of Mysore, Mysore, India. E-mail: November. [email protected] Donald G. Lindburg (corresponding author), Center for Reproduction of Endangered Species, Zoological Society of San Vegetation of the survey area Diego, PO Box 551, San Diego, CA 92112, USA. E-mail: [email protected] Although there are no forestry operations in this region at present, the area has been worked in the past for Received 14 August 1997. Accepted 18 June 1998 commercial purposes. As a result, most of the existing 1999 FFI, Oryx, 33(1), 31-37 Downloaded from https://www.cambridge.org/core. IP address: 170.106.33.22, on 26 Sep 2021 at 01:31:31, subject to the Cambridge Core terms of use, available at https://www.cambridge.org/core/terms. https://doi.org/10.1046/j.1365-3008.1999.00033.x 32 M. Singh et al. .20" Arabian Sea •10" L.f. ma/obo WESTERN GHATS no- EASTERN GHATS Fig. 1 Map showing the Eastern and MYSORE PLATEAU Western Ghats, the Mysore Plateau and the 7°E.longitud« approximate distribution of Loris tardigmdus lydekkerianus and L. t. malabaricus. forests are secondary or degraded. The predominant survey: (i) the area to be covered was fairly large; forest types can be described as follows: southern (ii) only a short period of time for survey work was tropical secondary moist mixed deciduous (Type 3B-C2- available; and (iii) lorises in the area were known to be 251); southern dry mixed deciduous (Type 5A/C3); active at night. It was decided, therefore, to concentrate carnatic umbrella thorn (Type 6A/C2); and southern primarily on the presence/absence of lorises in the Euphorbia scrub (Type 6A/C2/DS2; types from Champion different types of forest, using a vehicle to travel & Seth, 1968). Tree genera occurring in varying degrees through as many areas as possible in the time available. in these forest types are: Anogeissus, Acacia, Pterocarpus, Whenever possible vehicular survey was supplemented Albizzia, Dalbergia, Santalum, Terminalia, Azadirachta, by walks along pre-existing forest trails where a vehicle Tamarindus, Canthium, Euphorbia, Caparis, Dodonea, Cassia, could not be taken. The distance walked amounted to Aristida and Pterolobium. The understorey includes 21.5 km. No fixed point transect method was employed. shrubs of Carissa, Zyziphus, Randia, Lantana, Pterolobium, For this initial effort no attempt was made to determine Acacia, Cassia, Dodonea and Euphorbia. overall density or total population size. Most of the area had a good network of roads and Methods motorable tracks. Because the region is characterized by gentle hills, large patches of the forests on hill slopes The present work was carried out during November were visible from these roads/tracks. The sightings of and December 1996. The survey was restricted to the the animals were made by a party of 4-6 persons eastern part of Dindigul District in the forest ranges flashing powerful lights in all directions from the mentioned earlier. Because the forests of this region bonnet of a jeep. Travel was at a speed of 5-10 km/h. vary from open scrub to dense deciduous forests, the The presence of animals was determined by the orange survey areas were divided into five habitat types (Table reflection from the eyes when contacted by light. If 1). there was ever a doubt that another animal had been The following facts were considered in designing the mistaken for a slender loris the 'sighting' was either 1999 FFI, Oryx, 33(1), 31-37 Downloaded from https://www.cambridge.org/core. IP address: 170.106.33.22, on 26 Sep 2021 at 01:31:31, subject to the Cambridge Core terms of use, available at https://www.cambridge.org/core/terms. https://doi.org/10.1046/j.1365-3008.1999.00033.x Status survey of slender loris Loris tardigradus lydckkerianus in Diridigul, Tamil Nadu. India 33 DINDIGUL DISTRICT (EAST) FOREST Ayyalur Range Ayyalur Interface Division Nattam Block Sirumalai Block DISTRICT BOUNDARY Perumalai Block ROADS <C3 FOREST BOUNDARY Fig. 2 Forested areas in the eastern part of Alagar Hills 1-7 MORPHOLOGICAL SAMPLE SITES the Dindigul District in which the survey High Loris Density was conducted. discarded or the animal was approached on foot and Leg length: From tip of femur to tip of the the identity of the species determined. The total longest digit (cm) distance walked and motored amounted to about Foot length: From tip of calcaneous to tip of the 280 km. The surveys were conducted from 18.00 to longest digit (cm) 06.00 h. Arm length: From tip of humerus to tip of the Because subspecies identification in this area was longest digit (cm) unknown, diagnostic body measurements were taken Hand length: From wrist articulation to tip of the on seven representative animals (three adult males, two longest digit (cm) adult females, one subadult male, one unsexed infant). Head length: Distance from mid-orbital (frontal) to Subjects were restrained by hand to obtain body measure- tip of occiput (cm) ments and weights using standard sliding callipers and Head width: Distance between mastoid bones (cm) Chest girth: Circumference at breast height (cm; a sensitive weighing balance. Limb and body lengths using a cloth tape) required full stretching of the parts to be measured, and land marks were palpated through the skin. The following data were obtained: Results and discussion Body weight: Taken in g (rounded to l/10th of a g) Loris prevalence in different survey blocks Body length: From tip of snout to the vent (cm) Survey results from the different administrative blocks 1999 FFI, Oryx, 33(1), 31-37 Downloaded from https://www.cambridge.org/core. IP address: 170.106.33.22, on 26 Sep 2021 at 01:31:31, subject to the Cambridge Core terms of use, available at https://www.cambridge.org/core/terms. https://doi.org/10.1046/j.1365-3008.1999.00033.x M. Singh et al. Table 1 Number of lorises sighted in different habitat types No. of animals sighted Distance walked/motored Habitat type (km) Total Per km Dense Thorn Forest 21 0 0 Southern Mixed Deciduous Forest 28 18 0.6 Carnatic Umbrella Thorn and Euphorbia Open Scrub Forest 32 116 3.6 Crop lands close to forest 40 111 2.8 Crop lands away from forest 159 68 0.4 Total 280 313 1.1 revealed that the loris is distributed throughout the thorn forests could be scanned from the hill slopes at district, although undoubtedly in varying densities.