“Ring-tailed lemur society is ruled by a language of smells, displays and violence, and is teaching us about primate evolution” – Mike Unwin

It’s a hot day in Berenty Reserve, south-east Madagascar, and there’s a rumpus among the ring-tailed lemurs. Yips and squeals resound through the understorey as these spring-heeled primates bound around the roots of a tamarind tree. One young male advances with quivering tail arched forward over his head, only to be confronted by a rival doing exactly the same. In the shadows, a female performs a backwards handstand against a sapling.

To the enchanted groups of tourists watching these habituated lemurs, it looks like some kind of madcap primate circus. But, as their guides explain, the action is replete with meaning and to catch the gist you need only learn the lingo. This means not only translating the lemurs’ various yips, squeals, purrs, yells and wails, but also interpreting their sign language of posture, leap and grimace, and – even trickier to our untutored noses – their extensive repertoire of smells.

That’s right: ring-tailed lemurs say it with stink, using scent to convey strategic messages about territoriality, social rank and sexual availability. Olfactory communication is far more developed in lemurs than among monkeys and apes, and especially so in this species, which produces a pungent secretion from an array of scent glands. There are some on the inner forearms (antebrachial glands), some on the shoulders (brachial) and yet more in the ano-genital region (perianal).

Those two tail-waving individuals were indulging in a ’slink fight’. The handstanding female, meanwhile, was marking the group’s territory by smearing tree bark with scent from her vulva. A further glance around the group might also have revealed a male using special horny spurs on his wrists to gouge scent into the bark of saplings.

A MOST UNUSUAL LEMUR

“Madagascar’s trademark” was how the celebrated primatologist Alison Jolly once described the ring-tailed lemur.

Indeed, to people around the world it is emblematic of the island, and today that raccoon-like bandit mask and long black-and-white tail make the perfect symbol for the Madagascar National Parks Association.

Nonetheless, the ring-tailed is far from your typical lemur. For a start, it is much the most terrestrial of its kind – spending some 33 per cent of its time on the ground – and the most sociable, forming mixed-sex groups of generally 6-24 animals. It is also the most active by day, which makes it relatively easy to observe – and, crucially, to study. Jolly, who died this February, 2014,  began researching the ring-tailed lemurs of Berenty Reserve in 1963, continuing the study for four decades.

Central to her research were communication strategies. She discovered, for example, that ring-tailed lemurs use at least 28 vocalisations, ranging from soft contact calls, such as moans and meows, to howls audible from up to 1km away that advertise a groups presence to other groups in the area. Other sounds include contented purrs during grooming, chirps given when on the move, yips uttered by subordinates in the presence of superiors, and chutters given by a dominant individual upbraiding an inferior.

Taken in tandem with body language and scent-marking, this range of expression allows ring-tailed lemurs a complexity of social interaction that was once held to be the preserve of “higher” anthropoid primates – that is, monkeys and apes. Indeed, studies of anti-predator warning strategies among ring-tailed lemurs have revealed that they employ a specific vocabulary to distinguish between threats. Thus shrieks warn of a passing Madagascar buzzard or another bird of prey, while yaps are used when mobbing a predatory mammal, such as the mongoose-like fosa.

Learning the language of ring-tailed lemurs helped Jolly and her colleagues to unlock the secrets of their social life. It turned out that, in contrast with monkeys and apes, the lemurs live in a matriarchal society. While both males and females have separate dominance hierarchies within their sex, all females enjoy dominance over all males – a status that they readily assert by cuffing, lunging, biting and other displays of force.

Females stick together in their natal groups, with one high-ranking alpha female providing the central point for the group. Being the dominant sex, they maintain the groups territory – a fairly loose home range that overlaps with that of other groups. They will also take the lead in confrontations, driving off intruders with stares and other ritualised expressions of hostility. These interactions seldom lead to violence. Within their own troop, however, female dominance battles can turn ugly, resulting in serious injury or even expulsion.

Dominance hierarchies among miles are short-lived, and settled through stink fights and other ritualised displays. Competition is most intense during the breeding season, when it may erupt into “jump fights” – rivals leaping into the air and slashing at each other with their canines.

High-ranking miles inhabit the centre of a group, where they associate more with females than with other males. Lower-ranking individuals hang around at the periphery and often switch groups in the hope of more success.

STINK FIGHTS

During the breeding season, male ring-tailed lemurs engage in stink fights to compete for females and resolve conflicts without resorting to violence. They anoint their tails with pungent perfume by rubbing the fur against the scent glands on the insides of their wrists and shoulders. Then they arch their smelly tails over their backs and wave them, to waft the fragrance towards their rival, hoping to deter him by sheer force of body odour.

A stink fight breaks out when two males face off and start to pull their tails through these two glands. It lasts anywhere between 10 minutes and an hour, ending when one lemur backs down and flees.