The Lesser Known Primates
Frisky, bright-eyed lemurs rule the treetops
of the tropical
rainforest. Wild lemurs live only on Madagascar, a large island off the
east coast of Africa, and on the nearby Comoros Islands. Lemurs vary greatly
in size and appearance. The pygmy mouse lemur, for example, looks like a mouse
and weighs about as much as a slice of bread, 30
g. It is the smallest species of
lemur. The largest lemur, the indri, is about the size and weight of a large
house cat, 7
kg. It looks like a skinny black-and-white giant
panda bear.
Indris are one of the largest living lemurs. Their diet includes seeds,
fruit, young leaves, and flowers and they can weight up to 13kg (29lbs).
©G.Ellis/GLOBIO.org But lemurs are not related to mice or pandas. They are primates.
Lemurs are the most primitive type of primate, prosimians.
Compared to other primates, lemurs have smaller brains and rely more on their
sense of smell than their sense of sight. Also, their hands and feet are not
as well adapted for grasping as those of other primates.
Mysterious Island
Madagascar is home to 60 different kinds of lemurs ranging from the world’s
largest lemur to the smallest primate. The forests have provided shelter
and food for lemurs since they have lived there which may have been more
than 60 million years ago.
©G.Ellis/GLOBIO.org Scientists believe that millions of years
ago the ancestors of today’s lemurs did a strange and unexpected thing.
Those that lived in Africa hopped on logs and seaweed “rafts” and
drifted across the Indian Ocean to Madagascar. During an evolution that
lasted millions of years, different species developed. Lemurs’ behaviors
and adaptations evolved differently
from the primates in other parts of the world.
About 2,000 years ago, another species of primate settled on Madagascar: Homo
sapiens, or human beings. Their arrival spelled trouble for the lemurs.
Humans hunted lemurs for food and took over parts of their habitat.
By the 1600s, humans had driven about 16 lemur species to extinction.
How Many Species? Nobody Knows
Scientists are not sure of the number of
lemur species living today. But some of the best known include the brown lemurs,
ring-tailed lemurs, sifakas, indris, and ruffed lemurs. These species are diurnal,
or active during the day. Dwarf lemurs, mouse lemurs, and aye-ayes are some
species that are nocturnal.
New species are still being discovered. In 2005, scientists discovered two
new mouse lemur species. One is about the size of a squirrel. The other is
about the size of a hamster.
At Home in the Forest
Hop, skip, jump! That’s how sifaka lemurs travel across the ground. Their
legs and arms are long compared to their bodies – so bounding across
open areas, which they don’t like to do, is the quickest way to get
from one safe tree to the next!
©C.Ruoso/JH Editorial/Minden Pictures Lemurs are forest creatures. Many species
live in Madagascar’s tropical rainforests, but some live in dry deciduous
forests. The lemurs’ strong hands and fingers help them to climb trees
easily. Their muscular legs are adapted for jumping. When they need a change
of scenery, they hop to another branch.
Brown lemurs and ring-tailed lemurs scamper along the forest floor on all
fours. But other lemur species find traveling on the ground to be a challenge.
Their bodies just aren’t built for walking. Sifakas solve the problem
by hopping sideways on their back legs, as if they were on a pogo stick.
Feasting in the Forest
Many lemurs are herbivores.
They will eat almost everything the forest’s trees and plants have
to offer. Ring-tailed lemurs, for example, eat fruits, flowers, buds, bark,
sap, seeds, and leaves. Some species, such as the mouse lemurs, are omnivores.
They eat insects, eggs,
frogs, and lizards as well as plants.
This aye-aye has successfully found a grub and is enjoying its meal. Their
third or middle finger is very helpful for finding and grabbing insects.
The middle finger can be up to three times longer than its other fingers!
©F.Lanting/Minden Pictures The aye-aye eats insect larvae.
It has several adaptations that help it find larvae. Like bats and
dolphins, it uses echolocation to
find food. The aye-aye moves along a branch, tapping it with its middle finger.
Its huge ears listen carefully for an echo that signals that larvae are inside
the branch. Then the aye-aye rips away the bark with its teeth. It scoops out
the larvae with its hook-like third finger.
From Baby to Adult
Some lemur species, such as the dwarf and
mouse lemurs, have litters of two or more young. Others, such as the sifakas
and ring-tailed lemurs, give birth to one baby at a time.
After a few months, young lemurs are ready to find their own food. This
lemur is ready to explore its surrounding environment and forage for food.
©G.Ellis/GLOBIO.org After a baby lemur is born, it latches on to its mother’s belly, where
it stays hidden and safe from predators.
Like all mammals, it feeds on its mother’s milk. When it is a few weeks
old, the baby starts riding piggyback. After about three months, mom lets the
baby know it’s time to get off her back. She sends it off to find its
own food! Lemurs reach adulthood at about age three. They may live to be 20
to 25 years old.
Groups and Troops
Lemurs are social creatures and most of them live in troops. They benefit
from living in groups by getting protection, food and mating opportunities.
©G.Ellis/GLOBIO.org Lemurs stick together. Ring-tailed lemurs
form groups called troops with as many as 25 members. Sifakas and brown lemurs
live in smaller groups of 3 to 12. Why do they do it? There’s safety
in numbers. Hawks and other predators are less likely to attack a group than
a lone lemur. It’s also easier for lemurs to defend territory as
a group.
Making Their Mark
One way lemurs communicate with each other is with smells. Lemurs have scent glands at
their wrists, chests, and the base of their tails. Lemurs rub these glands
against twigs or branches to mark the borders of their group’s territory
and feeding areas. When rival groups of lemurs get a whiff of these markings
they either stay away or get ready for a fight.
Ladies First!
Usually, older female lemurs are in charge of a group or a troop. When conflicts
between groups happen, it’s the females who fight. First, they try to
scare the other group away with loud battle cries. If that doesn’t work,
they start biting and swiping at the rival females. Lead females also get the
best food and the comfiest places to sleep. If a male attempts to challenge
one of these ferocious females, she just might smack him!
Stink Fights
Male ring-tailed lemurs have an unusual way of fighting with each other. The
fight starts when one male grabs his tail and slathers it with stinky stuff
from his scent glands. Then he waves his tail at a rival male. The rival may
back off to get away from the bad smell. Or he may get his own tail in on the
action and try to stink out the other male. Stink fights sometimes last as
long as an hour!
Loudmouths
When danger is near, lemurs make a ruckus. After one lemur gives a piercing
warning call, others may join in. The sound of a dozen or so lemurs crying
out all at once—a behavior called mobbing—can be frightening. When
European explorers first heard mobbing lemurs, they thought they were hearing
the sounds of restless ghosts. In fact, the name “lemur” comes
from the Latin word for ghost.
Each species has its own set of calls that may include groans, snorts, yaps,
squawks, and screams. Certain calls warn others in the group of predators.
Other calls help lemurs stay in touch with members of their groups. For example,
if a sifaka is unsure of where the others have gone, it makes a call that sounds
like “sheef-auk.” This is how the sifakas got their name.
Looking Out for Lemurs
Madagascar has one of the highest levels
of biodiversity in
the world, with plants and animals that
are found nowhere else on Earth. But many of these plants and animals are endangered species.
Today, all species of lemur are in some danger of becoming extinct.
In fact, scientists rank lemurs as among the most endangered of all primates.
The local people of Madagascar sell materials from the forests such as charcoal
and plants. Humans cut down the forests of Madagascar for farming, shelter,
materials and industry. Habitat destruction threatens the survival of lemurs.
©G.Ellis/GLOBIO.org One reason lemurs are endangered is that people are burning and cutting down
Madagascar’s tropical rainforests to clear the land for farming and to
get wood for fuel. The loss of forests leaves lemurs with fewer places to live
and find food.
Hunting is another major threat to lemurs. Lemurs are a traditional food for
some peoples of Madagascar. Although it is against the law to hunt Madagascar’s
lemurs, some people do it anyway. Aye-ayes face a special danger. A traditional
belief, or fady, of the Betsimasaraka people calls for them to kill
any aye-ayes they see. Aye-ayes are thought to be bad luck. There are other fadys, however,
against killing other species of lemurs. These fadys may give some
protection to sifakas and indris but they are bad news for aye-ayes.
Scientists have singled out Madagascar as one of the world’s top priorities
for conservation.
The government of Madagascar has set up dozens of reserves to protect lemurs
and their habitat. Scientists have also started captive-breeding programs
that give the most endangered species a better chance of surviving.
Ecotourism in Madagascar gives people a chance to see lemurs in their natural
habitat and learn about the creatures. Some lemurs are as curious as tourists
so people are able to get a close-up experience with them.
©G.Ellis/GLOBIO.org International groups have teamed up with the Madagascar government to work
on conservation. They are looking for ways for people to make a living that
do not add to habitat loss. Ecotourism may
be part of the answer. Ecotourism can provide jobs that offer a sustainable way
of making a living and protect species and their habitat. Ecotourism also gives
visitors from around the globe the chance to see lemurs in their natural habitat
and understand the importance of saving them from extinction.