Elephants are able to differentiate between ethnicities and genders, and can tell an adult from a child – all from the sound of a human voice.
This is according to a study in which researchers played voice recordings to wild African elephants.
The animals showed more fear when they heard the voices of adult Masai men.
Livestock-herding Masai people do come into conflict with elephants, and this suggests that animals have adapted to specifically listen for and avoid them.
There is more here.