Lemurs only inhabit Madagascar, a small island off the coast of Africa. It is believed they arrived to Madagascar 65 million years ago on rafts of floating vegetables. Madagascar was formed during the break-up of Gondwanaland, 135 million years ago. 90% of the species found on Madagascar are endemic, meaning they can only be found on the island. As of 2012, 103 species of Lemur have been identified.
Lemurs are Strepsirrhini primates, this is not to be confused with chimps, monkeys, and humans which are all Anthriod primates. Strepsirrhini primates share many of the same morphological traits as Anthriod, including divergent digits and nails instead of claws. One main difference is their brain to body ratio is significantly smaller. All Strepsirrhini primates also have a rhinarium (wet nose), a pheromone detecting vomeronasal organ, lack of thin bone behind the eye (post orbital closure), orbits that do not fully face forward, and un-fused lower jaw bones. It is likely the original Lemur ancestor was a Loris another Strepsirrhi primate.
Lately lemurs of all kinds have been threatened due to the encroachment of humans on Madagascar. Animals that are isolated on islands have a history of doing poorly and often wiped out to extinction when a new predator (especially humans) is introduced. New Zealand's Elephant Bird was wiped out to extinction by humans, and now its much smaller relative the Kiwi is in danger from similar problems. Lemurs face the large human created issue of habitat destruction. The wide variety of Lemurs is do to extreme specialization. Each Lemur species is highly adapted to a very specific ecological niche, with some that are tree dwelling, some only live in water reeds, in places that one would never expect. Even a small portion of habitat being eliminated can cause a Lemur's entire ecological system to be extinguished. Humans also hunt Lemurs sometimes for food but more often as totems or even to ward off villagers from different tribes. Lemurs are a great example of an animal that is extremely sensitive and unable to adapt to habitat destruction even in the smallest of forms.
That's it for now,
Cass