Researchers from the Centre for DNA Fingerprinting and Diagnostics (CDFD) based Hyderabad were part of this extensive study conducted on Hanuman langurs in various pilgrim centers. The findings of this study were published on September 9 in the online preprint portal bioRxiv. According to the research, langurs develop a generalized tendency to choose their preferred food item and persistently reject anything else until they receive what they desire, often continuing to beg from the same person until satisfied.
The study identified eight distinct begging behaviors exhibited by these langurs, including bipedal begging (standing on two legs), quadrupedal begging (begging with all four legs on the ground), begging by embracing legs, begging by holding cloth, begging by holding hands, begging with aggression, passive begging, and provocation-initiated begging.
Interestingly, the researchers also pointed out that the langurs possess the ability to assess the mental state of humans and gauge their reactions to the food request signals. They meticulously observe whether their intended recipient has acknowledged their plea and wait patiently until they receive their desired food item. Essentially, these langurs use various gestures and begging postures to convey a single message: “Give me food.”
For their study, the researchers focused on a troop of free-ranging Hanuman langurs in Dakshineswar, West Bengal. This research sheds light on the fact that langurs not only understand the human state of mind but also demonstrate an impressive degree of goal persistence, ensuring they obtain their preferred food items.
The team of researchers behind this study included Dishari Dasgupta, Arnab Banerjee, Akash Dutta, Shohini Mitra, Debolina Banerjee, Rikita Karar, Srijita Karmakar, Aparajita Bhattacharya, Swastika Ghosh, Pritha Bhattacharjee, and Manabi Paul. Collaborating organizations included the Indian Institute of Science Education and Research, Kolkata, Sikkim University, Gangtok, University of Calcutta, Kolkata, WWF-India Sundarbans Programme, Kolkata, Centre for DNA Fingerprinting and Diagnostics, Hyderabad, and the University of California, Santa Barbara.This study provides valuable insights into the presence of intentional gestural communication within langur troops that have access to ample provisions. Furthermore, it suggests that pre-existing communication abilities in other primates, including the catarrhine lineage (Old World monkeys), may have played a pivotal role in shaping the evolution of human language.