Elephants show ear for human language
Elephants can distinguish the voices of dangerous men from friendlier folk. Yi-Di Ng reports.
Elephants are amongst the smartest animals on the planet: they use tools, mourn their dead, co-operate to solve problems, and are one of only nine species that can recognise themselves in the mirror. Now add to that list a remarkable ability to interpret human speech. New research shows they can tell harmless humans from dangerous ones, simply by listening to them talk.
Elephants can tell if you are male or female, young or old, and even what language you’re speaking just from the sound of your voice, say Karen McComb and Graeme Shannon, behavioural ecologists from the University of Sussex in the UK. From this information, the elephants gauge the level of threat, the team reported in the Proceedings of the National Academy of Sciences in March.
“This is a really exciting finding,” says Joshua Plotnik, head of research at the Golden Triangle Asian Elephant Foundation in Thailand. “It suggests elephant behaviour is extremely flexible and that they are learning to adapt to a growing threat within their environments – humans.”
The elephants in the study live in the Amboseli National Park in Kenya, land shared with humans for more than 500 years, and not always peacefully. The Maasai are a semi-nomadic tribe of cattle herders who depend heavily on their livestock to survive. During the dry season there is intense competition between their livestock and wild elephants for access to water and grazing ground. The Maasai drive away the elephants and sometimes spear them. The Kamba, by contrast, are a tribe of crop farmers who rarely encounter these elephants and pose little threat.
Earlier studies showed the elephants can distinguish Maasai from Kamba just by their smell and the sight of the Maasai’s red robes. Now, McComb and her colleagues have shown that the elephants have also learned to tell the two tribes apart by hearing their voices.
Elephants have excellent hearing, and very large brains
to process auditory information.
The researchers recorded grown men from the Maasai and Kamba tribes, as well as Maasai women and young boys, calmly saying the phrase, “Look, look over there, a group of elephants is coming,” in their own language. Over a two-year period, they played the recordings back to 47 elephant groups in the Amboseli National Park and recorded the elephants’ response.
When the elephants heard the voices of Maasai men, they reacted immediately, raising their ears and trunks in alarm and huddling together in a defensive formation before backing away. In contrast, the elephants did not react as fearfully to the voices of the Kamba men, the Maasai women or the Maasai boys. Even deliberate tricks couldn’t fool the elephants. The animals reacted fearfully even after researchers digitally raised the pitch of the Maasai men’s recordings to make them sound female.
The idea that elephants can discriminate threatening sounds is not entirely new: studies have shown they respond differently to the roar of male lions than to those of the less dangerous females. In the case of human voices, Shannon doesn’t think the elephants understand the words they are hearing. They are probably “picking up on the differences in the structure of the language and the distinct variation in tone,” he says. They have excellent hearing, and very large brains to process auditory information, he adds.
Having heard a threat, the elephants select a strategy to match. When McComb and Shannon played back recordings of a lion’s roar, the elephants responded aggressively, presumably to drive off the potential threat. But this isn’t what they observed with the human voice recordings. The elephants seemed to realise that they didn’t stand a chance against the spear-wielding Maasai, and tried to make a stealthy escape. Young elephants learn from older ones who have previously encountered humans, demonstrating the animals’ strong capacity for social learning.
While elephant cognition has been widely studied in the past, this is the first indication of how quickly elephants have adapted to cope with humans, says Plotnik.
“It’s another indication of their remarkable intelligence. Hopefully, the more we learn…the better able we will be to protect them in the wild.”