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Why Do Lemurs Live Only in Madagascar?

A ringtailed lemur suns itself in the desert sand. The lemur is known for this signature sitting position.  See more ­African animal pictures.
Keren Su/Getty Images

­The island of Madagascar, a country located about 250 miles (402 kilometers) off the coast of southeast Africa, is one of the ­most geograph­ically diverse places on the planet. Its terrain varies from beautiful coastal beaches and stretches of serene grassland to raging rivers winding through mountainous regions and dry expanses ­of desert. The island has a tropical climate with a rainy season lasting from December to April and a dry season lasting from May to November. Many distinct animal and plant species call this tropical paradise home. In fact, Madagascar is also home to some of the most unique and endangered plants and animals in the world. The lemur is one of these creatures.

Lemurs are primates, a group that includes monkeys, apes and humans. They're nocturnal, insectivorous creatures (meaning they feed on insects) with small bodies, long noses and large eyes. Eighty-eight species of lemurs exist today, all of which are native to Madagascar [source: Smithsonian National Zoo]. In fact, the reason lemurs have been able to thrive in Madagascar is because no other primates inhabit the island. But how exactly are lemurs different from other primates?

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Basically, primates can be broken down into two suborders: anthropoids and prosimians. Monkeys, apes and humans are anthropoids; lemurs are prosimians. Like other primates, prosimians rely on their moist noses and strong senses of smell to find food and identify individuals in their social group. They also groom themselves and others in their group. But while anthropoids use their fingers to groom, lemurs use their teeth as a comb. Anthropoids are omniv­ores — they usually don't actively hunt and rely mostly on vegetation and insects as food sources. Prosimians like lemurs are insectivorous and herbivorous creatures. Also, prosimian society is female-dominated. In this girl-power-driven suborder, females get the best food, defend the group and choose their own mates.

Prosimians evolved before anthropoids. The first prosimian fossil dates back 55 million years ago. The first monkey fossil dates back 45 million years ago, and the first ape, 35 million years ago. Before the anthropoids entered the scene, prosimians were pretty prevalent; fossils have been found all around the world, including in Europe, North America, Asia and Africa. But when the larger, more dominant, adaptive and intelligent anthropoids came into the picture, prosimians like lemurs were out-hunted. In the race against other primates for food, they lost. And, they began to die out all over the world. They disappeared from almost everywhere — everywhere except Madagascar.

The lemur doesn't exactly walk. Its gait looks more like ballet.
The lemur doesn't exactly walk. Its gait looks more like ballet.
Peter Arnold/Getty Images

One hundred and sixty million years ago, Madagascar was attached to the African mainland as a part of a supercontinent that consisted of today's Africa, South America, Australia, Antarctica, India and Madagascar. Lemurs already may have been on Madagascar when it separated from the African continent. But a more plausible theory suggests that because Madagascar separated from Africa by hundreds of kilometers before the evolution of lemurs, these primates crossed over from Africa by floating on large bunches of vegetation. Once they settled on the island, they became reproductively isolated and free from the threat of other primates. In fact, the only reason they still survive there today is because of Madagascar's isolation.

Competing primates like monkeys and apes never made it to Madagascar. So the lemurs that floated over to the island thrived — competing only among themselves for the best food sources — and wound up evolving into many different species. The lemurs that didn't escape to the island met a very different fate. African lemurs became extinct when they couldn't compete with other primates for food, and the same thing happened elsewhere around the world. A 30-million-year-old fossil of a modern dwarf lemur, Cheirogaleus, was found in central Pakistan, for example [source: National Geographic News]. But no such animal exists in that part of the world today.

­This isolation from other primates ended, however, when the first human settlers arrived on the island from Malaysia and Indonesia about 2,000 years ago. The arrival of humans wreaked havoc on the lemur populatio­n. The larger species of lemur suffered the most. Viewing large, fearsome looking, gorilla-sized lemurs as threats, humans hunted them. Today, the largest lemur, the Indri, is tiny in comparison to the over-sized lemurs that once inhabited Madagascar. The Indri weighs only 15 to 20 pounds (6.8 to 9 kilograms). But fossil records indicate that the largest extinct lemur species, Archaeoindris, weighed between 350 and 440 pounds (158 to 199 kilograms) [source: PBS]. By the time Europeans arrived to Madagascar in the 1500s, 15 species of lemurs had already become extinct. Today, all lemurs are endangered species. Humans not only have hunted lemurs but have also destroyed their habitats through deforestation.

Three captive lemurs get cozy.
Three captive lemurs get cozy.
Gary Vestal/­Getty Images

Lemurs continue to live in almost all of Madagascar's ecosystems and terrains, and they range in size from the 25-gram pygmy mouse lemur to the 15- to 20-pound (6- to 9-kilogram) Indri [source: Smithsonian National Zoo].

Today there are 88 species of lemurs living in Madagascar [source: Smithsonian National Zoo]. Researchers believe that 10 to 20 previously undiscovered species may be found in the next generation [source: Wild Madagascar]. Lemurs are also found on the nearby Comoros islands; it's generally believed that they were introduced to the area by humans.

Twenty-one percent of all primate genera, the taxonomic groups above species, and 36 percent of all primate families, the taxonomic groups above genus, live in Madagascar. That makes the island a target for preserving and protecting the primates for research. Despite their ecological importance, humans have steadily contributed to the destruction of primate habitats. Eighty percent of the island's forests have been destroyed, mostly for logging or crop cultivation purposes.

­Due to Madagascar's economic constraints — the average per capita income is equal to about $200 — and large population of over 14 million people, subsistence for humans outweighs preservation. However, efforts are being made to preserve the lemur and the island's biological diversity, or variation of life forms, in a way that can also help Madagascar's people. Madagascar's diverse geography, which contributes to the variance of the life forms living there, is one of the most unique in the world. Due to both its beautiful landscape and varied animal and plant population, ecotourism has become an increasingly popular industry in Madagascar. It may be the a key to preserving this primate on the verge of extinction [source: Wild Madagascar].

We can also learn much about our own primate pasts from the lemur. Lemurs are less closely related to humans than monkeys and apes. They more closely resemble the primates that existed tens of millions of years ago. Even so, by studying lemur development, researchers might be able to find out more about the human evolutionary process [source: Smithsonian National Zoo].

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More Great Links

Sources

  • Duke Lemur Center. http://lemur.duke.edu/
  • Glander, Dr. Kenneth. "What's a Lemur?: Madagascar: A World Apart." PBS. http://www.pbs.org/edens/Madagascar/creature2.htm
  • "Lemurs." Smithsonian National Zoological Park. http://nationalzoo.si.edu/Animals/Primates/Facts/FactSheets/Lemurs/
  • "The Lemurs of Madagascar." Lemurs: Ghosts of the Forest. http://www.lemurs.us/Madagascar.html
  • Nature: A Lemur's Tale- Spirits of the Dead. PBS. http://www.pbs.org/wnet/nature/lemur/spirits.html
  • "Lemurs of Madagascar." Wild Madagascar. http://www.wildmadagascar.org/wildlife/lemurs.html
  • Ratsimbazafy, Jonah. "Fighting for Madagascar's Lemurs." Guardian Weekly. August 8, 2008. http://www.guardianweekly.co.uk/?page=editorial&id=684&catlD=4
  • Trivedi, Bijal P. "Do Pakistan Fossils Alter Path of Lemur Evolution?" National Geographic News. Oct. 22, 2001.http://news.nationalgeographic.com/news/2001/10/1022_TVlemur.html

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