Illustration of caribou eyes by Christina Nelson

Photo By/Credit

Christina Nelson /USFWS

Date Shot/Created
Media Usage Rights/License
Public Domain
A special adaptation for caribou that experience total winter darkness in the very farthest northern regions: a membrane in their eye changes color to reflect different wavelengths of light — summer gold reflects most of the light back out of the eye, while winter blue scatters more light inside the eye, giving the caribou a better chance to spot predators in the dark. Art by Christina Nelson/USFWS.