Hair is important, and not just for humans, but for all mammals. Hair serves many functions. It keeps us warm, provides camouflage for both predator and prey, and many species even use hair for communication. Despite its significance, the evolution of wild primate hair is not very well understood.
In an effort to determine how climate, body size, and color vision may have influenced hair evolution, researchers with the Primate Genomics Lab at the George Washington University looked at a wild population of Indriidae, a type of lemur endemic to Madagascar.
The experts found that Sifaka lemur hair is denser in arid, open habitats. They hypothesize that similar to its function in humans, this type of hair helps protect the lemur from the sun.
The researchers also discovered that lemurs that lived in cooler environments had darker hair. They believe that the animals adhere to Bogert’s Rule, which declares that animals who live in colder environments develop darker hair which helps them thermoregulate since darker hair absorbs more heat.
Interestingly, red hair in lemurs is more likely to be seen in populations that can perceive a more extensive range of colors. Nonetheless, several evolutionary pressures influence hair structure and color; this means that these effects will not be found in all lemur species.
Unfortunately, it is not easy to understand the evolution of human hair by looking directly at ancestral hair because it does not fossilize, which is why researchers turned to lemurs.
“The lemurs we studied exhibit an upright posture like humans and live in a variety of ecosystems like early humans, so our results provide a unique window into human hair evolution,” said study lead author Elizabeth Tapanes, a postdoctoral scholar at UC San Diego.
The scientists hope that by studying non-human primates such as lemurs, we can gain a better understanding of our own evolutionary history.
“Most people are intrigued by the diversity of hair on their own bodies, and the variety of hair types among people around the world,” said study co-author Professor Brenda Bradley.
“Understanding hair patterns in non-human primates, such as these lemurs, may provide a comparative context for understanding how variation arose in human hair.”
The study, “Hair phenotype diversity across Indriidae lemurs,” is published in the American Journal of Biological Anthropology.