Black Lemur

11th June 2010

At least 50 species of fruit trees in Madagascar depend on black lemurs to distribute their seeds. This is a vital contribution primates make to their natural habitat – without them, many seeds would not be removed from their tough husks. Furthermore, some seeds can only grow after they have been through the digestive system of a primate! Just like bees, black lemurs are also responsible for pollinating some plants.

Physical description: The name of black lemurs is deceptive, in that only males are actually black with yellow eyes (although another subspecies has blue eyes). Females are golden to reddish-brown with dark faces, light undersides, long white ear tufts and orange eyes. Their average body length is 41cm and tail length 55cm, although females may be slightly larger than males. On average, they weigh just under 2.5kg. 

 

Habitat: Black lemurs live around the area of Narinda Bay in northwestern Madagascar and on the islands of Nosy Bé and Nosy Komba. They like to live in primary and secondary rainforest, but due to the increasing destruction of their preferred habitats, some have adapted to timber, nut or fruit plantations.

 

Diet: An estimated 78% of black lemurs’ diet consists of fruit, and they have been observed to eat at least fruit from at least 70 different tree species. They also eat leaves, flowers, nectar, mushrooms and millipedes. Black lemurs may also feed on cashews, mangos, papaya, citrus or coffee fruits grown on plantations. Lemurs often feed by suspending themselves upside down from branches by their feet.

 

Life history: Black lemurs are born after a gestation period of just over 4 months. Females have their first offspring at the age around 2 years and subsequently give birth no more than once a year, around September to November. Offspring can be a single infant or twins, which are carried around by the mother for up to 1.5 years. Young males and females have been observed to leave the group between the ages of 1-2 years. On average, black lemurs live about 27 years in captivity.

 

Associations: Black lemurs may live in the same areas as Coquerel’s dwarf lemur, although this species is nocturnal so they presumably interact very little. However, in the dry season when there is less fruit available, black lemurs have been found to be quite active at night too.

 

Social structure: Group size ranges between around 4-14 individuals, depending on the composition of the forest and availability of fruit. Larger groups are dominant over small ones, and groups may split if they become too large. Furthermore, males often leave their group during the mating season and females also sometimes move to different groups. There are roughly equal numbers of males and females in a group, though a higher proportion of males may also be found, which is extremely rare amongst primate groups. As with most prosimians, females are dominant over males, which may result in males being chased or even physically assaulted!

 

Territorial marking: Black lemurs scent-mark by rubbing their ano-genital region on branches or tree trunks. The males have additional scent glands on their wrists and head, with which they vigorously mark their territories.

 

Communication: Black lemurs have various calls to keep the group together, some of which sound surprisingly like quacking ducks! They also make small grunting noises when travelling through their habitat and purr like cats during grooming. Territorial calls are reported to be given by entire troops at dusk, although these vocalisations have not been heard at Monkeyland. However, loud territorial calls may be heard in response to territorial calls from our black & white ruffed lemurs, who would not normally share territory with black lemurs in Madagascar. Loud calls ending in a whistle are given as alarm calls to warn the group about predators such as birds of prey or dogs. In the case of humans, who are also a serious threat to black lemurs, huff-grunts have been recorded accompanied by rapid swishing of the tail back and forth. Subsequently, the group would flee from sight.

 

Mating: Aggression between groups increases during the mating season (April-June), presumably due to males competing for female attention. Generally, a dominant male will try to monopolise mating. However, one subordinate male was observed to mate with a female 6 times in 30 minutes whilst the dominant male was not around!

 

Other behaviour: Our resident black lemur Brad was very shy when he arrived from a Canadian zoo with severe cataracts in both eyes. He could hardly see and kept bumping into things. We worried that he could never be released. Everyone was very relieved when his eyes were successfully operated on by a South African specialist in Johannesburg. When he recovered from the operation he was released into Monkeyland with our female black lemur, Angelina. In their cage, Angelina had always been the bouncier one of the two and was dominant over Brad. Upon release, however, Brad immediately explored his new habitat whilst a terrified Angelina clung to the same tree for several days! They are now both happily integrated into the Monkeyland forest.

 

Conservation: Black lemurs are classified as vulnerable to extinction by the IUCN. They are also listed on Appendix 1 of CITES. Major threats are habitat loss and degradation due to agriculture, crops, shifting agriculture, wood plantations and wood extraction, as well ongoing development of infrastructure for humans. There are also reports of illegal hunting in the black lemur. One intensively researched group lost 40% of its members in a five-year gap between studies. The black lemur population is considered to range between 10,000-100,000 individuals.

 

Did you know? Monkeyland is exactly the size of a normal black lemur group’s territory in Madagascar (12ha).

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