What is a meerkat? Meerkats (Suricata suricatta) are small (<1 kg) mongooses found in arid regions of southern Africa. They feed mainly on insects, arachnids and small vertebrates, and spend much of their time digging in the sand in pursuit of their prey. Unlike many other small mammals in such environments, meerkats are strictly diurnal. By night, they shelter in elaborate burrow systems; at dawn they emerge to roam their territories, which may extend for several square kilometres and encompass dozens of overnight burrows and hundreds of emergency ‘bolt-holes’ that provide refuge from predators such as eagles or jackals. What kind of a name is ‘meerkat’ anyway? Meerkatzen is the Germanic name for Cercopithecine monkeys, which in turn probably derives from the Sanskrit for monkey — markata. Presumably, to the explorers that first described meerkats, their appearance and/or behaviour was reminiscent of monkeys. So now you know. Is Timon from Disney's The Lion King a fair representation of a meerkat? Not really… In the wild, a solitary meerkat is a rare and typically short-lived phenomenon; indeed, the single most striking thing about meerkats is that they are highly social animals. They live year-round in tight-knit groups of up to 40 individuals presided over by a dominant female and a dominant male who fathers most of the litters born in the group. What's so special about meerkat sociality? Meerkats exhibit a rich repertoire of cooperative behaviours. Observe a group of meerkats at their burrow at the end of a day's foraging, and you'll see piles of individuals huddling together for warmth and grooming one another. You may also see digging teams working together to maintain the tunnels of their burrow. By day, while the group forages, individuals take turns to stand guard atop nearby bushes or termite mounds. These sentries scan the sky and surroundings and signal to the group at the first sign of approaching danger. When rivals are encountered, meerkat groups band together to defend their territories, and the crucially important burrows they contain. At other times, they mob together to ward off larger predators, such as cobras. Cooperation is most striking, however, when it comes to rearing young. The matriarch produces most of the group's offspring, but raising these pups is a responsibility shared by all group members. For the first month, helpers babysit pups at the burrow, losing up to 11% of their body mass in the process. Older females may even suckle the young. Later, when the pups begin to forage with the group, helpers provision them with a large share of the prey that they manage to find. Is life as a meerkat a Utopian idyll? In meerkats, as in our own society, cooperation is seldom to be found without its ugly twin, conflict. Throughout the day, foragers frequently attempt to steal prey items from one another, but the most serious conflicts occur over who gets to breed. Males from rival groups, prospecting for receptive females, are often attacked by resident males, and dominant males jealously guard their mates during oestrus. Competition for dominance is fierce: a coup d'état is always a threat, and a regime of bullying is necessary to keep order in the ranks. If a subordinate female falls pregnant, she risks a brutal beating, or worse, expulsion from the safety of the group. Even if she does manage to stay until giving birth, her newborn pups may well be killed by the dominant female. Why do meerkats cooperate? Social evolution theory would suggest that meerkat cooperation may largely be down to high levels of genetic relatedness: by helping to raise the offspring of relatives, individuals indirectly transmit copies of their own genes. In meerkats, however, this is not a complete explanation, because unrelated immigrants may help just as much as other group members. Research suggests that, in the harsh environment in which meerkats live, belonging to a group — the larger the better — is absolutely vital. Without sentries, meerkats cannot feed safely; without helpers, they cannot breed successfully; without strength in numbers, they cannot hold territory. Through cooperation, individuals can increase the size and success of their group, and in so doing, improve their own individual prospects for survival and reproduction. Do all meerkats help equally? No, research has shown that the amount of help provided typically depends on the ability to help: well-fed individuals are more likely to expend energy for the benefit of others. But this is not to say that meerkats simply help indiscriminately. Female helpers, for example, preferentially feed female pups — probably because these pups, being the philopatric sex, represent the future workforce that might one day help to raise the helpers' own litters. How is it that we know so much about meerkats? Meerkats' striking sociability and their tendency to become habituated to the presence of human observers, make them eminently tractable model organisms for investigations into the evolution of social behaviour. A large-scale, long-term field study of meerkats in the southern Kalahari was initiated in 1993 by Tim Clutton-Brock of the University of Cambridge. This project, involving hundreds of thousands of man-hours of detailed behavioural observations coupled with long-term pedigree and life-history information has provided a wealth of data on cooperative breeding behaviour and constitutes the best database of such information that exists today for social mammals. What else have we learned from meerkats? Apart from serving as a model for the evolution of cooperation, the Kalahari meerkats have provided unique opportunities for research in other areas of biology too. Through observation and experiments, Marta Manser and her group at the University of Zurich have ‘decoded’ many of the 30 or so calls, and the numerous postures, displays and olfactory signals that meerkats use. This work extends our understanding of animal communication and cognition. For example, meerkat alarm calls, which categorise threats according to both class and urgency, exhibit a level of complexity more typically associated with humans. Other behavioural studies have used meerkats to investigate why animals play, and recently they were used to neatly demonstrate that animals can, and do, actively teach their young. On the ecological front, meanwhile, meerkats have provided insight into the demographics, dispersal, and population genetics of social carnivores. For instance, long-term population data clearly demonstrate the “Allee effect”: if meerkat group sizes fall too low, recruitment tails off rapidly and local population crashes can ensue. Finally, at a physiological level, meerkats are helping us to better understand the energetics, endocrinology and thermoregulation of small desert-adapted mammals.