Elephants can determine ethnicity, gender, and age from acoustic cues in human voices

Abstract

Animals can accrue direct fitness benefits by accurately classifying predatory threat according to the species of predator and the magnitude of risk associated with an encounter. Human predators present a particularly interesting cognitive challenge, as it is typically the case that different human subgroups pose radically different levels of danger to animals living around them. Although a number of prey species have proved able to discriminate between certain human categories on the basis of visual and olfactory cues, vocalizations potentially provide a much richer source of information. We now use controlled playback experiments to investigate whether family groups of free-ranging African elephants (Loxodonta africana) in Amboseli National Park, Kenya can use acoustic characteristics of speech to make functionally relevant distinctions between human subcategories differing not only in ethnicity but also in sex and age. Our results demonstrate that elephants can reliably discriminate between two different ethnic groups that differ in the level of threat they represent, significantly increasing their probability of defensive bunching and investigative smelling following playbacks of Maasai voices. Moreover, these responses were specific to the sex and age of Maasai presented, with the voices of Maasai women and boys, subcategories that would generally pose little threat, significantly less likely to produce these behavioral responses. Considering the long history and often pervasive predatory threat associated with humans across the globe, it is likely that abilities to precisely identify dangerous subcategories of humans on the basis of subtle voice characteristics could have been selected for in other cognitively advanced animal species.T he ability to recognize predators and assess the level of threat that they pose is a crucial cognitive skill for many wild animals that has very direct and obvious fitness consequences (1-5). Until recently, most research in this area focused on how a range of birds and mammals classify other animal predators, demonstrating complex abilities to differentiate between predators with different hunting styles and respond with appropriate escape tactics (2, 3, 6-8). However, for many wild populations, humans represent a significant predatory threat (5, 9, 10) and this threat is rapidly increasing as areas for wildlife decrease and humananimal conflict grows. Moreover, as it is typically the case that not all humans pose the same risk to prey species, distinguishing between different human subgroups to identify those associated with genuinely threatening situations could present a major cognitive challenge. The extent of behavioral flexibility that different species may exhibit in correctly classifying human predators-and the degree of sophistication possible in such abilities-is therefore of considerable interest.Most research on the abilities of animals to classify human predators has focused on discrimination through facial features or general differences in behavior and appear...

Extraordinary elephant perception

“…Such fine discriminatory abilities may help distinguish dangerous from nondangerous encounters with one of the most threatening species on the planet: ours. This is precisely the task that McComb et al set for themselves using the highly social African elephant as their test subject (10).…”

“…Considering recent research on the impact of an elephant matriarch's experience and age on her herd's survivability (12,13), it is not surprising that individual life experience might also influence how elephants react to different potential threats. McComb et al (10) provide suggestive data that the age of the herd's matriarch affects their response to Maasai boys, with older matriarchs less likely to retreat from their voices than younger matriarchs. In another study, herds led by older matriarchs reacted more appropriately to threats from male lions than those led by younger, less experienced females (12).…”

Crop Damage by Wild Herbivores:Insights Obtained from Optimization Models

“…Different species of herbivores differ in their population size, gregariousness, activity periods, qualitative and quantitative patters of damage and response to guarding and driving attempts 13,35,36 . In cases where the probability of damage is small, a crop insurance scheme can be a viable proposal even if the extent of damage is large.…”

Habituation to Auditory Stimuli by Captive African Elephants (Loxodonta africana)

“…African and Asian elephants use their learning abilities to maintain social cohesion in their large family/bond groups and deal with challenges in their ever-changing environment [Bates et al, 2007;McComb et al, 2014Soltis et al, 2014]. However, both species are currently listed on the IUCN Red List of Threatened Species [IUCN, 2014].…”