Wild Asian elephants distinguish aggressive tiger and leopard growls according to perceived danger

Abstract

Prey species exhibit antipredator behaviours such as alertness, aggression and flight, among others, in response to predators. The nature of this response is variable, with animals reacting more strongly in situations of increased vulnerability. Our research described here is the first formal study to investigate night-time antipredator behaviour in any species of elephants, Asian or African. We examined the provocative effects of elephant-triggered tiger and leopard growls while elephants attempted to crop-raid. Tigers opportunistically prey on elephant calves, whereas leopards pose no threat; therefore, we predicted that the elephant response would be reflective of this difference. Elephants reacted similarly cautiously to the simulated presence of felids of both species by eventually moving away, but differed markedly in their more immediate behavioural responses. Elephants retreated silently to tigergrowl playbacks, whereas they responded with aggressive vocalizations, such as trumpets and grunts, to leopard-growl playbacks. Elephants also lingered in the area and displayed alert or investigative behaviours in response to leopard growls when compared with tiger growls. We anticipate that the methods outlined here will promote further study of elephant antipredator behaviour in a naturalistic context, with applications for conservation efforts as well.

Asian Elephants (Elephas maximus) Discriminate Between Familiar and Unfamiliar Human Visual and Olfactory Cues

“…African elephants can adjust their visual signals based on the human's apparent attentiveness during interactions (Smet & Byrne, 2014), can use human pointing as a cue to find hidden food (Smet & Byrne, 2013; although Asian elephants failed to do so, Plotnik et al, 2014), and can discriminate between types of threatening stimuli (Soltis, King, Douglas-Hamilton, Vollrath, & Savage, 2014). Wild Asian elephants have demonstrated the ability to distinguish between leopard and tiger growls, with elephants retreating silently from tiger growls (a potential predator of elephant calves) and retreating while vocalizing when exposed to leopard grows (which pose no threat, Thuppil & Coss, 2013). Given the sensory and discriminatory abilities of elephants, it may be possible for Asian elephants to distinguish between different categories of humans.…”

Playback of felid growls mitigates crop-raiding by elephantsElephas maximusin southern India

“…When elephants tripped a beam from a Takenaka PB-60 TK infrared receiver–transmitter system, a wireless link activated playback of a single sound exemplar selected at random by the mp3 player from 2–3 exemplars of tiger growls, leopard growls or human shouts (Thuppil & Coss, 2013). The infrared transmitter was aligned to project a pulsed beam c. 60 m to a receiver.…”

“…Our playback growls were recorded by Uma Ramakrishnan from one tiger and one leopard at the Bannerghatta Zoological Park, Bangalore, using a Sennheiser ME 80 directional microphone coupled to a Sony TC-D5 PROII analogue recorder. Both felids were agitated similarly to engender growling: the keeper entered their cages and banged a stick repeatedly (Thuppil & Coss, 2013). The procedure was not repeated with other individuals because of the potential danger involved.…”

The use of audio playback to deter crop-raiding Asian elephants

“…Previous studies of elephant vocal communications have shown that Asian elephants can comprehend and differentiate among calls of different individual elephants (Bittner ). It has also been found that elephant behavior can be manipulated by other natural sounds that threaten them (Vollrath and Douglas‐Hamilton ; King et al , ; McComb et al ; Thuppil and Coss ). The sound of disturbed African honeybees ( Apis mellifera scutellata ) elicited an alarm call from African elephants (King et al ), which subsequently moved away from the sound.…”

“…The presence of African honeybees also deters elephants from damaging the vegetation and trees that contain their hives. It has also been reported that wild Asian elephants can distinguish between aggressive tiger ( Panthera tigris tigris ) and leopard ( P. pardus fusca ) growls according to the perceived danger (Thuppil and Coss ). It has even recently been suggested that elephants can distinguish among different groups of humans and assess the threat that a person poses them based on acoustic cues in their voice (McComb et al ).…”