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Monday, March 17, 2014

Elephants discriminate between human voices

If you’re a wild African elephant of mature age, you’ve probably had a number of encounters with humans, some of which you undoubtedly regret. Of course, not all humans pose the same threat to your little band, so it would be useful if you could distinguish potential predators from mere passersby. The good news is that you can!

Two groups of people that elephants commonly encounter are the Maasai and the Kamba. The former are much more likely to come into deadly conflict with the elephants than the latter. Consequently, elephants show more fear when exposed to either the scent or red color of garments worn by Maasai men than to clothes worn by Kamba men.

Researchers from the University of Sussex and Amboseli Trust for Elephants investigated whether elephants could also distinguish between human voices. To that end, they recorded Maasai and Kamba men and women saying “Look, look over there, a group of elephants is coming” in their own languages. The recordings were played back to groups of female elephants (females and juveniles typically travel separately from adult males).

All the groups displayed more fearful, defensive behavior after hearing male Maasai voices than they did for Kamba voices or for female Maasai voices. They bunched together and spent more time carefully sniffing the air. It should be noted that Maasai women are not involved in hunting elephants and thus pose no real threat to the animals.

Interestingly, when the recordings were acoustically altered to make men sound like women and vice versa, the elephants still showed fear only when hearing what were originally male voices. In other words, the elephants could tell the men from the women even when the men sounded like women to our ears.

I don’t find it that surprising that elephants can distinguish men from women by their voices, though it is a bit odd that they seem to be better at it than we are. I do find it amazing that African elephants can tell the men from two different tribes apart by their voices. This suggests that elephants can discriminate between human languages, a remarkable ability.

By the way, aural perspicacity goes both ways. Another new study shows that humans can tell how old elephants are by listening to their vocal calls. 

McComb, K., Shannon, G., Sayialel, K., & Moss, C. (2014). Elephants can determine ethnicity, gender, and age from acoustic cues in human voices Proceedings of the National Academy of Sciences DOI: 10.1073/pnas.1321543111.

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