New research reveals that a chimpanzee’s hair color says little about his age.
In humans, gray or silver hairs indicate that they are getting older. And the more gray hair they have, the older they usually are. But what about our closest relative: the chimpanzee? Scientists at George Washington University figured it out. And guess what? Chimpanzees are a bit different.
The researchers collected and extensively studied photos of wild and captive chimpanzees. It specifically looked at how many gray hairs the chimpanzees had. Then they looked at how old each chimpanzee was when the photo was taken.
And so they discovered that the number of gray hairs said little about the age of the chimpanzees. For example, chimpanzees with a lot of gray hair were not always considerably older than their peers with little gray hair.
“People have a fairly linear and progressive pattern,” says researcher Elizabeth Tapanes. “You get grayer as you get older. We don’t see that pattern with chimpanzees. ” The apes gradually become grayer until halfway through their lives – how gray they become differs from chimpanzee to chimpanzee – and then their hair color hardly changes as they get older. “Chimpanzees are reaching a point where their hair gets a little salt and pepper color, but they never turn completely gray, so you can’t use those hairs to estimate their age.”
Hypotheses It is
not clear on the basis of this research why chimpanzees – unlike us humans – do not go completely gray. But the researchers do have ideas about it, they write in the journal PLoS ONE . For example, the chimpanzees might be able to regulate their body temperature better with their rather dark hair. Also, because they hardly change color, it may be easier for chimpanzees to recognize each other.
To date, surprisingly little research has been done on graying chimpanzees or other wild animals. Instead, a lot of research is being done into the physiological processes that lead to people – often unwillingly – becoming gray and how we can possibly thwart those processes. However, it can be very helpful to look beyond humans and view the graying hair from an evolutionary perspective.
In any case, the researchers are not yet done with the graying chimpanzees. For example, they plan not to look at gene expression in individual hairs of the great apes. In this way they hope to find out whether there may be changes at the genetic level that are related to the changes that we can see with our own eyes: namely the graying of the hair of the chimpanzee.