Patterns of hand use in golden langur (Trachypithecus geei) during feeding in a fragmented habitat of Western Assam, India.

Abstract

Golden Langurs Trachypithecus geei are selective feeders and feed on variety of food plants throughout its life time. Handling and procuring of the food items by Golden Langurs have been observed in field, while they are feeding on different food items in Kakoijana Reserve forest, Assam. It has been observed that depending upon the food item the langurs used different techniques for eating them. Out of 6833 observations, it was recognized that they used six different techniques for handling the food item. The techniques include Pluck and hold with left hand (PLR) collecting and holding the item in left hand and then eat from hands, Pluck and hold with right hand (PHR) collecting and holding the item in right hand and then eat from hands, Pluck and feeding with right hand (PFR) collecting and feeding the item with right hand , Pluck and feeding with left hand (PFL) collecting and feeding the item with left hand, Both hand (BH) feeding collecting and holding the item in both hands and then eat from hands, Bending and Towing methods, when foods are collected directly from the food plant either towing the plant towards them or bending itself towards the food plant. For a leafy food item Golden Langurs pluck the leaf and eats by hand and sometimes they pluck a handful of leaves and put directly to the mouth. In cases of small fruits like Syzygium cumni, they collect the fruits either with right or left hand one by one with fingers and put them into mouth. Our data show that there is individual variation in hand preferences for feeding among the Golden Langurs.