Elephants will probably never displace dogs as peoples' best friends, but they apparently can know humans quite well.

So say researchers from the University of Sussex in the United Kingdom, who've discovered elephants in Africa are able to identify people who pose a threat by distinguishing between the languages and voices of differing ethnic groups.

As described in the March 10 edition of Proceedings of the National Academy of Sciences, researchers ventured to Amboseli National Park in Kenya, where family groups of elephants were played audio recordings of the Maasai people, who periodically confront elephants over access to water and grazing areas for their cattle, and the Kamba, whose largely agricultural lifestyle causes fewer conflicts with elephants.

Elephants involved in the study were more likely to demonstrate defensive behaviors -- such as grouping together and investigative smelling -- when they heard male Maasai voices, as opposed to male Kamba voices.

As well, the elephants showed less defensiveness when listening to the voices of Maasai women and boys, indicating an ability to assess the sex and age of voices when figuring out the most threatening situations.

"Recognizing predators and judging the level of threat they pose is a crucial skill for many wild animals," Karen McComb, lead author of the study and a mammal communication expert, said in a news release. "Human predators present a particularly interesting challenge, as different groups of humans can represent dramatically different levels of danger to animals living around them."

Previous studies showed elephant family groups exhibiting greater fear to the scent of garments worn by Maasai men than Kamba men and show heightened states of aggression when shown red clothes that the Maasai typically wear.

Graeme Shannon, the study's co-author, noted being able to run threat assessments on sounds, from which an elephant family can can determine the ethnicity, gender and age of a potential predator, has the distinct advantage of serving as an early warning system, particularly if a predator can't be seen.

"The human language is rich in acoustic cues. The ability to distinguish between Maasai and Kamba men delivering the same phrase in their own language suggests that elephants can discriminate between different languages," Shannon said. "This apparently quite sophisticated skill would have to be learned through development or through younger family members following the lead of the herd's matriarch and other older females."