A new study on Hanuman langurs has shed light on their remarkable abilities to communicate for food. The study, conducted by researchers between January 2019 and April 2021, observed the behavior of 140 free-ranging Hanuman langur troops in various parts of West Bengal, India. Contrary to previous beliefs, the study found that intentional gestural communication is not exclusive to humans but is also present in other non-human primates like langurs.
The researchers discovered that langurs use various gestures to convey a single message: “Give me food.” These gestures include 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. These eight begging gestures are used by langurs of all ages except infants.
The study also highlighted the langurs’ ability to assess the recipient’s mental state. The langurs persistently check if the signal (food request) has been received and wait until they receive the desired food item. This behavior demonstrates their cognitive abilities and their understanding of the recipient’s intentions.
The findings of this study are in line with recent discoveries of intentional gestural communication in both catarrhine and platyrrhine primates. The researchers noted that langurs’ communication strategies are efficient in directing begging events to success. While the most common begging gesture is by holding cloth, provocation-initiated begging and begging by embracing legs efficiently lead to successful outcomes.
Understanding primate communication and behavior is crucial for comprehending the cognitive abilities of different species and the evolution of communication systems. This study provides valuable insights into the unique communication strategies employed by Hanuman langurs and expands our understanding of primate behavior. Further research in this area can provide additional insights into the complexity and versatility of non-human primate communication.
