No need for a red nose—reindeer vision peers into the dark

Reindeer don’t need Rudolph to find their way at night. Researchers found that the ungulates can see light in the ultraviolet spectrum, aiding their ability to find food in the dark Arctic winter.

“Reindeer are so cool, but many people think about them only at Christmas,” said Dartmouth professor Nathaniel Dominy, first author of a recent study in the journal i-Perception.

Reindeer—known as caribou (Rangifer tarandus) in the North American wild—subsist primarily on a lichen known as reindeer moss, or Cladonia rangiferina. To the human eye, the white lichen is nearly invisible against the snow. But reindeer moss and a few other lichen species they eat absorb UV light. Using spectral data from the lichen and light filters calibrated to mimic reindeer vision, researchers found that these lichen appear as dark patches against a bright background.

“Getting a visual approximation of how reindeer might see the world is something other studies haven’t done before,” Dominy said.

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