Reindeer’s blue eyes act as night vision goggles to help them find food in winter

Scientists photographed various lichen beds in the Cairngorms mountains in Scotland and found the reindeer’s favourite strongly absorbed UV light. Photograph: Murdo MacLeod/The Guardian

Rudolph does not need to use his famous red nose to guide his fellow reindeer as the animals have a special form of night vision that they use to forage for food, scientists have concluded.

Researchers looked into why the species are the only mammals whose eyes change colour depending on the season, from golden-orange in summer to a blue hue in the winter months.