Lemurs are a group of early primates that survive only on the island of Madagascar and nearby Comoros islands.
Lemurs are often said to be a primitive form of primate but I prefer the term early because it means they evolved from an early form of primate. Lemurs are a kind of pro-simian which is a suborder of primates which are themselves of the order of mammals. Sounds complicated but about 55 million years ago the first pro-simians became a distinct species, a suborder of primates. They branched off from the evolutionary path that resulted in apes and monkeys. The species that would become the lemurs existed in Africa, though it may not have originated their, in the distant past.
At some point some of that species migrated from Africa to Madagascar. It was believed that they traveled across a land bridge that connected Africa to Madagascar but recent geological evidence has shown that Madagascar was already separated from Africa by water when the first pro-simians arrived their. The current theory is that they crossed from Africa to Madagascar on floating vegetation, I choose not to comment.
In Africa the species, which on Madagascar evolved into the Lemur, became extinct. This was probably due to competition with other primates which evolved later, fortunately for the Lemur Madagascar was by then completely cut off from Africa so those later species of primates never got to Madagascar until very recently.
On Madagascar the ancestors of the Lemur thrived until quite recently. Five distinct families and many different species of lemur evolved as they spread across the island and adapted to all of its distinct environments. Upon arrival the Lemur would have had no natural predators and ample food supplies.
Lemurs have the binocular vision and grasping hands that characterize all types of primates but lack many of the more advanced characteristics of primate evolution. This shows that they separated early from the from the rest of the primate evolutionary path but also that their was no need to evolve these characteristics within their new environment. Possessing less well developed hands, slightly smaller brains and relatively solitary lifestyles it is likely that the lemur were already well equipped to deal with the environment they found themselves in. Rather than developing advanced social structures to aid in the gathering of food and defense they instead remained primarily solitary gatherers and gathered only in relatively small groups.
Lemurs did adapt in some ways to their environment, they have relatively long, slender limbs adapted to climbing and leaping and most species have long tails that aid their balance when leaping from tree to tree.
The final stage of Lemur evolution began about 2000 years ago when the first humans arrived on Madagascar. By the mid 1600’s when the first Europeans arrived on Madagascar fifteen species of Lemur had become extinct. These were the largest species of lemurs including of comparable size to an adult gorilla, another that clung to trees like a koala bear and the sloth lemur. Their size may indicate that they were seen as competition for food, a target for hunters or simply that like many large species they were simply too slow to adapt to a changing environment.
