Not long ago I read about Vervet monkey. Here's picture:

enter image description here My question is what causes this blue coloration of the scrotum? I don't mean evolutionary need (e.g. attracting females), but what pigment or other factor is responsible for this color?

  • 2
    $\begingroup$ I've suggested an edit to your post; in the future please upload pictures rather than including links. Links are discouraged since 1) if they break they no longer add value to this post, and 2) they can be used to link to malicious websites. Thanks! 😊 $\endgroup$ – tyersome Nov 29 '19 at 23:16
  • 3
    $\begingroup$ A related question about blue food that doesn't answer your question, but you might find it interesting: Why are so few foods blue? $\endgroup$ – theforestecologist Nov 30 '19 at 17:22

Blue coloration in animals is caused by structural color rather than blue pigments. In the case of vervet monkeys and other mammals studied this is due to collagen fibers in the skin being arranged with a regular spacing that results in blue wavelengths constructively interfering while other wavelengths destructively interfere1.

This "news" article in Science discusses this phenomenon and mentions Vervet monkeys.


1: Prum, R. O., & Torres, R. (2004). Structural colouration of mammalian skin: convergent evolution of coherently scattering dermal collagen arrays. Journal of Experimental Biology, 207(12), 2157-2172.

| improve this answer | |
  • $\begingroup$ Excellent! (+1). It's always nice to see such useful primary literature cited here on Bio.SE! Can you elaborate a tiny bit more from the paper (i.e., describe the tissue arrangement more explicitly etc.)? -- Not necessary, but I think doing so would make the answer stand better on its own (in case links died and someone can't get access to the paper). $\endgroup$ – theforestecologist Nov 30 '19 at 17:32

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.