African elephants have the ability to distinguish between human languages, researchers have determined. A team of researchers found that elephants in the Amboseli National Park region of Kenya have learned to differentiate between the dialect of the Maasai tribe, whose members have a history of killing elephants, and the languages of other tribes that present less of a danger to them, National Geographic magazine reported Monday. The researchers' findings, published in the Proceedings of the National Academy of Sciences, contribute to "our growing knowledge of the discriminatory abilities of the elephant mind, and how elephants make decisions and see their world," Joyce Poole, an elephant expert with ElephantVoices in Masai Mara, Kenya, told National Geographic. Earlier research found elephants can tell the difference between the Maasai and members of the neighboring Kamba tribe, by scent and color of their clothing, National Geographic said. The researchers determined the elephants' language recognition ability by playing audio recordings to 47 elephant families over a two-year period and observing the animals' reactions. They found when the matriarch of an elephant family hears a Maasai man, speak, "she instantly retreats," said Graeme Shannon, a behavioral ecologist at Colorado State University in Fort Collins. "But it's a silent retreat. They sometimes make a low rumble, and may smell for him, too, but they're already leaving, and bunching up into a defensive formation. It's a very different response to when they hear lions." Hearing the voices of Kamba men didn't elicit nearly as strong a defensive reaction, indicating they didn't consider them a serious threat. "That subtle discrimination is easy for us to do, but then we speak human language," Richard Byrne, a cognitive biologist at the University of St. Andrews in Scotland, said. "It's interesting that elephants can also detect the characteristic differences between the languages."