DOI: 10.5061/dryad.g79cnp5w1
title: Intentional gestural communication in Hanuman langur

description: Contrary to previous beliefs, intentional gestural communication (IGC) is
 not exclusive to the hominoid lineage but is also present in other
 non-human primates. Here, we report the presence of IGC among free-ranging
 Hanuman langur troop in Dakshineswar, West Bengal, India. These langurs
 exhibit a food-requesting behaviour wherein they use several gestures to
 communicate with the humans nearby. Moreover, they can also assess the
 recipient's mental state and persistently check if the signal (food
 request) has been received, waiting until they receive the desired food
 item. We have identified eight begging gestures used by langurs of all
 ages, except infants. The most common gesture is by holding cloth (BGc),
 but provocation-initiated begging (BGpi) and begging by embracing legs
 (BGe) efficiently direct these events to its success. The frequency of
 successful begging events is higher in the evening due to increased human
 interactions. Our findings suggest that ontogenetic ritualization might be
 at play here among these troop members as this gestural communication has
 been learned through imitation and reinforced by the reward of receiving
 food. Moreover, these successful begging events serve as an effective
 foraging strategy for urban-adapted langurs, allowing them to acquire
 high-calorie processed food items within a human-modified urban
 ecosystem. 
description: This dataset was collected through field-based observation in a
 field site spanning three years. We carried out field observation across
 three sessions of three hours each - Morning , Afternnon and Evening.
 Observations consisted of 10 minutes of All Occurence Sampling (AOS) and 1
 minute Scan done randomly across three sessions of the day.
description: # Intentional gestural communication in Hanuman langur --- We found that
 these langurs exhibit first-order intentional gestural communication
 wherein the langurs acknowledge the mental state of the human recipient,
 exhibit means-end dissociation and show signs of waiting for the human to
 respond to it's gestural call. The given dataset contains details of
 begging (intentional gestural communication) events observed in the langur
 troop of Dakshineswar. We observed langurs during different time slots of
 the day following Altman(1976) with a combination of AOS (10 minutes) and
 Scan(1 minute). These langurs use around eight different postures to
 communicate with nearby human and ask for food. From our observations we
 have noted down the different postures, the total number of successful
 begging, total number of begging shown by the different age groups -
 Adult, sub-adult, Juvenile and Infant. Given that this study troop has
 high adult females, this age group has been found to have a high impact on
 the outcome of begging event alongwith the begging posture that involves
 pulling of human's clothes. ## Description of the data and file
 structure The following data structure contains around 20 columns having
 different data points. Column A has slot details S1 (Session 1: Morning),
 S2 (Session 2: Afternoon) and S3(Session 3: Evening) Column B to Column I
 contain details of begging events executed by the free-ranging langurs in
 the eight postures described in the manuscript. PA: Bipedal begging, PB:
 Quadrapedal begging, PC: begging by embracing human legs, PD: posture
 involving langur pulling human hand, PE: begging with aggression, PF:
 posture involving langur pulling human's cloth, PG: passive begging,
 PH: provocation inititated begging Column J (PS: Successful begging
 events) has details of successful begging events that occurred during the
 observation period. Column K to Column N has details of begging events
 shown by different age groupd of langurs - Column K: (BA) Adult, Column L:
 (BS) Subadult, Column M: (BJ) Juvenile and Column N: (BI) Infant Column O
 to Column T has details about the food offering sequence number from
 humans where B1 stands for food offered after one round of begging, B2
 stands for food offered after second round of begging, B3 for food offered
 after the third round of begging, b4 for food offered after fourth round
 of begging, B5 and B6 for food offered after the fifth and sixth round of
 begging respectively. There are 84 rows out of which 83 rows contain
 details of begging events recorded for different sessions(see Column A
 description about session) during the observation period. ##
 Sharing/Access information Not applicable ## Code/Software Not applicable