Meerkats recognise each others' voices

Meerkats recognise another member of their social group by the sound of their voice, according to scientists. Researchers studying the animals in the Kalahari Desert, South Africa, played recordings of meerkat calls and observed the animals' reactions. Their discovery, reported in the Royal Society journal Biology Letters is the first evidence of a non-primate showing vocal recognition in the wild. The phenomenon could be more widespread in the animal kingdom than thought. "There's lots of evidence of vocal recognition in primates," explained lead researcher Dr Simon Townsend from the University of Zurich in Switzerland. "[In primates] you can really test whether they respond to individual vocal recognition." But this harder to test in other non-primates, he explained, because relationships between individual animals are not as clear. In meerkats, for example - although they are social animals that live in groups and forage and even raise young together - it is not entirely clear how one animal will respond to another when it hears its call. To solve this problem, the researchers used a simple audio playback experiment. They used recordings of the staccato "close calls" that meerkats make continually while they are foraging. "We think the calls mainly function to keep the group together," said Dr Townsend. "But they also tell other individuals, 'I'm here, this is my patch'." Comparing meerkat reaction The next part of this experiment presented the animals with a puzzle; after playing the call of a meerkat from one side, the researchers immediately played a call from the same animal, through the opposite speaker. Dr Townsend explained that this was a "violation of the animal's expectation"; it would be "physically impossible" for the same meerkat to be in both places. "The meerkats showed more vigilance when their expectations were violated," explained Dr Townsend. "They would stop foraging, orientate their ears towards the violation, or look in that direction." The researcher explained that recent research had shown that vocal recognition seemed to be "present in lots of different branches of the evolutionary tree". "It's possible that animals living in complex [social] systems need to be able to keep track of each other. But given how widespread it appears to be... it could have a much deeper evolutionary origin. The team hopes that this simple playback experiment will help other scientists to study the phenomenon across a wide range of species. Prof Richard Byrne, an animal communication expert from the University of St Andrews, said the experiment gave "simple and irrefutable evidence of vocal individual recognition". "It could certainly be used with a range of other species," he told BBC Nature.