Lemurs

From Mgias

Contents 1 Introduction 2 Lemur Classification 2.1 The Sub-fossil Lemurs 3 All about lemurs 3.1 Life cycle 3.2 Social life 3.3 Grooming 3.4 Scent and smell 3.5 Calls 3.6 Diet and positional behavior 3.7 Sexual colour differences 4 Lemur Species within the 5 Regions 4.1 The Western region 4.2 The Northern Region 4.3 The Central Region 4.4 The Southern Region 4.5 The Eastern Region

Introduction

Madagascar is well known for its unique flora and fauna, including lemurs, primitive small carnivores (civets, mongooses, cryptoprocts), tenrecs (insectivores ), colorful chameleons,and baobab trees. It’s mammals are primitive and smaller compared to those of nearby African mainland. The lemurs, carnivores and tenrecs, representing 5/6 of the country’s mammals are extinct from the rest of the world because they has remained isolated from Africa until the present day.

Madagascar has been described as a “world apart” because of the uniqueness of its animal and plant species. The island is the last refuge for several endangered species, particularly the lemurs. Lemurs are primitive primates that became extinct in the rest of the world some 30 million years ago and survive only in Madagascar. The 32 lemur species range from the world’s smallest primate, the Pygmy Mouse Lemur, weighing only 25 grams to the largest living lemur, the Indri, weighing more than 8 kilograms.

The nocturnal Aye Aye, with its fascinating extended skeletel middle finger and rodent-like ever-growing bottom teeth is extraordinary! These two features, essential to the Aye Aye's existence, are used as follows:

1. It's fingers tap on trunks of trees or outside of coconuts to determine whether there is food inside
2. It's teeth gnaw through these tough exteriors
3. It's unique finger scoops the food out.

The Aye Aye is a very endangered lemur species, and a high priority for conservation.

Because of the loss of forest cover caused by human activities such as slash and burn agriculture, bush fires and logging, most of the lemurs are gone forever. Additionally, several species are at risk of extinction because of the severe destruction of their forest habitat. So, the country is a top conservation priority for primates. Madagascar has the 3rd highest primate diversity, with 5 living lemur families, 14 genera and over 32 species with more than 54 varieties, including the various sub-species. There are also 20 extinct species. In addition, new species have been recently discovered but have not yet been recorded.

Lemur Classification

The living lemur belongs to 5 families:

1. The CHEIROGALEIDAE or dwarf lemurs (mouse, dwarf, fork marked dwarf : nocturnals).
2. The LEMURIDAE or true lemurs ( ring-tails and ruffed lemur or Varecia : diurnals).
3. The LEPILEMURIDAE or MAGALADAPIDAE ( sportive lemur : nocturnals).
4. The INDRIDAE ( indri , sifaka or propithecus diurnal ,and the nocturnal wolly or Avahis).
5. The DAUBENTONIIDAE with monotypic species (nocturnal).

Since the arrival of humans most of the forest habitats are under threat. Along with the giant lemurs, other indigenous creatures such as dinosaures, elephant birds, pygmy hyppopotatamus, and some species of tortoises are gone forever. Other living species have become at risk of extinction in the last few decades.

The Sub-fossil Lemurs

Exctinct giant sub-fossil lemurs are found in the swamp and cave deposits throughout Madagascar. Strangely, sub-fossils of surviving lemur species are rare in those caves and swamps sites.

These giant lemurs were represented by at least 5 families:

1. Daubentoniidae or extinct nocturnal giant aye-aye, which is related to the living aye-aye
2. Lemuridae which is is related to the ruffed lemur or Varecia,
3. Megaladapidae, the size of a gorilla size is related to the sportive lemurs
4. Archaeolemuridae and Palaropropithecidae which are the tree-dweling “sloth lemur” and are related to living indris, sifakas, and avahis.

All the sub-fossil giant lemurs are diurnal and folivorous except for the Daubentoniidae family or extinct nocturnal aye-aye. This lemur had an elongated third finger and rodent-like incisors which enabled it to extract grubs and insect larvae from the dead wood of tree trunks.

All about lemurs

Lemurs we see in Madagascar today are smaller than the extinct ones, and range from 25 grams to up to 8 kilograms, while the extinct lemurs ranged from 10 to over 100 kilograms.

Life cycle

The vast majority of the lemur species are active during the day. The largest lemurs are strictly diurnal. These consist of Sifaka ,Indri and the Ruffed lemur. The middle sized species tend to be cathemeral (diurnal and nocturnal). These consist of Brown lemurs and Mongoose lemur. Strict nocturnality tends to occur only among the smallest bodied lemurs species including Mouse lemur,the Dwarf lemur, Sportive lemur and Woolly lemur or Avahis. Nocturnality helps small-bodied arboreal mammals avoid predation by diurnal raptors. Cathemerality is a transitory phase that nocturnal arboreal lemurs must pass through to become diurnal.

Social life

Like the other prosimians,lemurs live in family groups and use scent and calls to communicate within the group and to the others. The size of the group differs from one species to another. Some live in small group of 2 to 5 individuals like the largest species Indri. Other species like the ringtails live in large troops of 15 to 25. Additionally, most of the nocturnal lemurs are solitary , and they live in pairs during the breeding season.

Grooming

Lemurs have an important social life and grooming is part of their every day life. Lemurs use their teeth as a comb, because they don’t have the ability to articulate their fingers for this purpose.

Scent and smell

Lemurs have long muzzles with moist noses and an acute sense of smell. Scent and smell play an important role in lemur’s behavior and is used for communication as well as gathering and marking their territories. Most of the females have an anal gland from which they squirt fluid on the base of a tree. Males such as ringtails have this gland located on their wrists, while other species of lemur like the broad nosed bamboo lemur have this territory-marking gland located under their chin!

Calls

Voice or calls are also very essential not only for lemurs to communicate to each other, but also to warn a danger against predators like the carnivores “Fosa” and raptors. But calls are also very useful to define wide territories that scent can’t cover. The Indri’s loud call that can be heard 3 kilometers away and advertise the presence of the groups within their ranges.

Diet and positional behavior

The lemurs are mainly folivorous and frugivorous, but nocturnal lemurs add some gum, plant galls, insect larvae and insect in their diet. However it is important to realize that diet and positional behahaviour are related. Most specialized leapers like the indridae feed mainly on leaves. Although the indridae family is the most specialized leaper, they share with their relatives, the sifaka and the woolly lemur, the ability to use the long powerful forelimbs to rotate the body in flight. The indridae and the megaladapidae or sportive lemur are vertical climbers, while the other families are arboreal quadruped. Of these, the ringtails are most terrestrial, moving quadrupedally on the ground of the dry spiny forest and gallery in the Southern Region

Sexual colour differences

Lemurs have beautiful fur and their color depends on the species and sometimes also on the sex. Some species like the Eulemur species are sexually dichromatic, the male being brown with black crown while the female is gray with brown crown. In other species such as the black lemur or Eulemur macaco, the color of the females is brown and differerent from the colour of the mames which in this case is black.

Lemur Species within the 5 Regions

The Western region

Many species of lemurs are reported to live in the dry deciduous forest of the Beharama National Park. Among these are:

1. Decken’s sifaka,
2. Verreaux’s sifaka
3. Brown lemur
4. Red tailed Sportive lemur (nocturnal,)
5. The fork marked dwarf lemur (nocturnal).

The Ampijoroa and Kirindy forests are worth visiting because they have a wonderful collection of indigenous flora which are home to some endangered species of lemurs. These include

1. the mongoose lemur,
2. coquerel’s sifaka,
3. the nocturnal Ravelobe mouse lemur, (Ampijoroa forestry station: Ankarafantsika national park) and
4. the nocturnal Pigmy mouse lemur weighing about 25grams (Kirindy forest).

The Northern Region

In the Northern Region, the native vegetation is home of rich biodiversity and endangered species of lemurs which are restricted to this region. These include

1. the golden crowned sifaka lemurs(propithecus tattersalli)an endangered lemur of Daraina
2. the northern fork marked dwarf lemur
3. the rare black sifaka lemurs
4. the golden crowned sifaka lemurs
5. the indigenous black lemurs which live in the lush vegetation of Lokobe Reserve on the offshore Island of Nosy Be and also on Nosy Komba

The Central Region

The fascinating "ruiniform" sandstone Isalo massif of the Central Region has been sculpted by the blistering wind into weird shapes and cut through with impressive canyons. This houses three lemur species

1. The ring-tailed lemur,
2. Verreaux’s sifaka and
3. The brown lemur.

The Southern Region

The Southern Region houses the ring tailed lemur.

The Eastern Region

The protected areas in this region are lovely sanctuaries with many species of lemurs, including the amazing Aye Aye.