Black-and-white Ruffed Lemur

11th June 2010

Black-and-white ruffed lemurs (BWRLs) have one of the longest names in the animal kingdom, so to make things easier we will call them BWRLs. Lemurs are primates, but they are not monkeys. Along with bushbabies, tarsiers, pottos and lorises, they form the primate suborder of prosimians or “pre-monkeys”.  BWRLs are closely related to red ruffed lemurs, with the main difference being their distinct colouration.


Physical Description: BWRLs are one of the largest living lemurs, with an average head and body length of 50cm and tail length of 60cm. They weigh around 3.5kg, only 1% of which accounts for their brain weight. Like most prosimians, lemurs have an elongated nose, almost like a snout, and are heavily reliant on their sense of smell.  Ruffed lemurs are named after their fluffy collars, which look like a beard running from ear to ear below the face. BWRLs are black and white, as their name suggests, though some have bits of brown fur. Individual BWRLs have varying amounts of black and white, depending on the particular area they come from: animals from the northern areas of their range have more black and southern ones have more white. The individual distribution of black and white, especially on their backs, is the main factor used to tell them apart at Monkeyland.


Habitat: BWRLs are found in eastern Madagascar, which is situated 400km off the east coast of Africa and is the fourth largest island in the world. Madagascar has a diverse lemur population, with 69 known lemur species and subspecies. BWRLs are arboreal, preferring the high canopy of the primary rainforest. They are currently protected in the Verezanantsoro, Mantady and Ranomafana National Parks, the Andringitra, Betampona and Zahamena Nature Reserves and in the Ambatovaky, Nosy Mangabe and Analamazaotra Special Reserves.


Diet: BWRLs largely feed on fruit but also eat seeds, leaves and nectar. They are the most frugivorous (fruit-eating) of all lemurs. This fruit-eating habit is very important in that they disperse seeds throughout the forest and therefore ensure the growth of new trees. At Monkeyland, BWRLs are particularly fond of sweet potatoes, grapes, bananas and oranges, but they have also been observed to eat leaves, shoots, flowers and berries in the forest.


Life History: BWRLs females build one or more nests prior to the birth of infants. They are the only primates to do so solely for the rearing of offspring. In captivity, including here at Monkeyland, BWRLs have been observed to build nests on the ground. In the wild however, nests are built in trees. While females can have up to six babies, litter sizes usually range from 1-3 infants. The largest litter seen at Monkeyland has been triplets. Gestation lasts just over three months. Infants at Monkeyland are usually born between late October and early December. They are kept in the nest until they are 4-6 weeks old. Youngsters do not ride on the mother’s back or stomach like other primates, but instead are transported one by one in the mother’s mouth. When infants are about 2 weeks old, the mother will begin to park her babies in trees while she goes out to forage.  The little ones are relatively safe because their mother may use up to 7 different parking sites over the course of the day. BWRLs also exhibit alloparenting, which means that adults will help care for infants that are not biologically theirs. In terms of growth, BWRLs mature faster than other lemurs. By 4 months of age, they weigh 70% of the average adult weight. By comparison, brown lemurs are only 50% of their adult weight by the same age and ringtail lemurs are just 40%. BWRLs become sexually mature around 18-20 months of age. Their lifespan is 15-20 years.


Associations: No known associations.


Social Structure: The social structure of BWRLs consists of a large community, which is subdivided into a varying number of groups. This type of social organization is known as fission-fusion sociality. The high demands of foraging and long distance travel for food are thought to be related to this rare type of social structure. Fission-fusion sociality is also found in the spider monkey, which has a similar diet to BWRLs. Like with other lemurs and prosimians in general, females are dominant in this species.


Territorial Marking: BWRLs use scent marking and vocalizations to denote their territory. Scent marking in BWRLs is gender-specific, although occasionally individuals will show scent marking of the opposite gender. Males typically use glands on their neck and chest to scent mark, while females usually mark with the anogenital region. At Monkeyland we have observed an increase in scent marking around the mating season.


Communication: BWRLs use vocalizations as well as olfaction (smell) to communicate. Because BWRLs spend a considerable amount of time spatially distant from one another, they have a number of high-frequency calls that allow individuals or small groups to maintain acoustic contact with the rest of the community. BWRLs have at least 13 distinct vocalizations. One of the most commonly heard sounds in the Monkeyland forest is the BWRLs roar/shriek chorus. When one individual gives this call, everyone in the area typically joins in, thus creating a wonderfully loud lemur choir. Occasionally one of our ringtail lemurs will even join in at the end of the production. Studies of wild BWRLs have shown that infants start to join in the roar/shriek chorus around 4 months of age.  BWRLs also have a special call used just between the mom and the infant.  


Mating: BWRLs are only sexually active during their mating season. BWRLs are reproductively photosensitive, with mating beginning after the winter solstice when the light to dark ratio is increasing.  Prior to female oestrus, both males and females undergo changes in their social behaviour and genitalia. Females are only sexually receptive for one day during their oestrous cycle, but may cycle up to three times during the mating season. During mating, males mount females from behind. Signs of pregnancy are observed six to eight weeks after conception.


Other Behaviour: Like sifakas and ringtail lemurs, BWRLs are frequent sun-bathers. They can often be found reclining in high trees, soaking up the rays. BWRLs are also very acrobatic and love to hang by their feet. At Monkeyland they have been observed to hang during play, self-grooming, feeding and occasionally just for fun! BWRLs are also crepuscular, which means they are active at dawn and dusk.


Conservation: Although BWRLs do extremely well in captivity, they are currently classified as endangered by the International Union for the Conservation of Nature and Natural Resources (IUCN). Field studies have observed some behavioural flexibility in BWRLs following temporary habitat destruction, such as that caused by extreme weather. When faced with permanent habitat loss however, BWRLs are usually one of the first species to disappear. BWRLs will not survive continuous destruction inflicted by humans. Rainforest in Madagascar is currently being razed for the logging, mining and agriculture industries. As of 2000, only an estimated 90,000 square kilometres of primary forest and woodland area remains. The population estimate for BWRLs is just as alarming, with only 1,000-10,000 individuals left in the wild. Apart from the creation of national parks and reserves, conservation efforts include the reintroduction of ex-captives to the wild. BWRLs are the only lemur to be reintroduced into the wild to date. Thirteen ex-captives have been released into the Madagascar Betampona Nature Reserve since 1997. In order for this and other potential reintroduction programs to be successful, we need to ensure that habitat destruction and poaching are no longer threats. Please do your part by encouraging eco-friendly products and educating at least one person about the plight of the amazing black and white ruffed lemur.


Did You Know?Monkeyland has twenty-two BWRLs, the majority of which were named after famous people. Our BWRL group includes such greats as Darwin, Einstein, Shakespeare and Madiba. Madiba is the nickname of Nelson Mandela, the first democratically elected president of South Africa.