Being able to recognise other individuals in your social group requires a certain level of cognitive ability and is thought to have been crucial in the evolution of animal societies. While we already know quite a bit about our close family, the primates, very little is known about the rest of the animal kingdom. Townsend et al., (2001) recently published a study giving clear evidence for vocal individual recognition in wild non-primate animals. They studied meerkats, who rely on vocal communication to coordinate their activities according to their environment where there is the constant risk of predation.
At the Kalahari Meerkat Project in South Africa they used a dual-speaker set up to simulate an incongruent (test) condition and a congruent (control) condition.
In the incongruent condition they played the call of a subordinate individual who appeared to be relaxed and foraging on one side of the subject and then played the call a few seconds later, several metres on the opposite side of the subject. The theory was that by presenting different calls from the same individual it would create an impossible situation which would violate the expectations of the listening subject; it would cause confusion due to the same meerkat appearing to be in two places at once.
In the congruent condition they simply simulated the presence of two relaxed and independently foraging meerkats on opposite sides of the subject.
In both the conditions, subordinates from the same group were used in order to rule out that the discrimination of different individuals may depend upon their position within the social group.
They found that the meerkats were more vigilant and were vigilant for longer during the incongruent condition and that they were also more likely to look towards the speaker, in comparison to the congruent condition.
This suggests that when confronted with an impossible social situation (the presence of the same meerkat in two places at one time), the meerkats were able to detect that there was something wrong with the scenario. The researchers were able to conclude that the meerkats were capable of distinguishing between individuals.
As meerkats live in relatively stable, cooperatively breeding social groups that can be as large as 50 individuals, it is important for them to be able to keep track of other group members with whom they may have competitive or cooperative relationships. This allows for the successful maintenance of their social systems. Close calls which indicate the position and identity of the caller may be a way in which the meerkats are able to maintain their social system.
This is an important finding as it helps us understand how animals are able to interact with others within their social groups, which is vital in understanding the evolution of our own sophisticated social and communicative capacities.
Image credit – Kirsty Matthews
Townsend, S.W., Allen, C. & Manser, M.B. 2011. A simple test of vocal individual recognition in wild meerkats. Biol. Lett. Published online 12 October 2011 (doi:10.1098/rsbl.2011.0844)