Rudolph shouldn’t lead Santa’s sleigh with his red nose because reindeer can’t see the colour – and nor can they see carrots left out for them, scientists say
- They can’t see red, orange or green according to research by Exeter University
- Reindeer have ultraviolet vision and use it to see lichen in the snow in the Arctic
- Rudolf the reindeer was first imagined in 1939, spawning hundreds of stories
- Reindeer eyesight is similar to dogs, who are also unable to tell difference between the three colours
Rudolph couldn’t have led Santa’s sleigh because they are colourblind and would not be able to see the light from their crimson snout.
Reindeer lack the colour-detecting eye cells that humans have to detect red, University of Exeter scientists have revealed.
They are also unable to see orange and green, meaning the animals might struggle to spot any carrots left out for them under the Christmas tree.
However, they do have ultraviolet vision to spot lichen hidden in the snow and to spot white wolves or predators.
They are able to do this because their fur absorbs UV light whereas snow reflects UV light.
This remarkable visual ability is part of the reindeer’s unique adaptation to the extreme Arctic environment where they are found.
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Rudolph the reindeer probably wasn’t bullied for his crimson snout – because he and his fellow reindeer can’t see red. The animals, associated with Christmas and Santa, cannot see orange or green either
‘Reindeer can’t see red light or tell the difference between red, orange and green,’ explained Professor Martin Stevens, of the Centre for Ecology and Conservation on the University of Exeter’s Penryn Campus in Cornwall.
‘So they wouldn’t be able to see the red of Rudolph’s nose or the orange of carrots.
‘They do have ultraviolet vision, and use this to see lichen hidden in the snow in the arctic.
This can potentially be used to spot white wolves or other predators because fur absorbs UV light whereas snow reflects UV light.
‘So a camouflaged white wolf to us would stand out to reindeer,’ said Professor Stevens.
The research was compiled by Professor Stevens and teams from Exeter University as part of their Science of Christmas talk in Cornwall.
Aside from the UV vision, the eyesight of reindeer is similar to that of dogs, which are also unable to tell the difference between red, orange and green.
Professor Stevens and his colleagues’ work on animal vision also includes horses, leading to a trial of new colours on fences at racecourses.
The animals have been proven to protect their eyes from being damaged by UV light, which is thought to be harmful to human vision.
Reindeer do however have ultraviolet vision to spot lichen hidden in the snow in the arctic and spot white wolves or predators. They are able to do this because their fur absorbs UV light whereas snow reflects UV light
A study published in 2011 in the Journal of Experimental Biology discovered that reindeer can not only see ultraviolet light but they can also make sense of the image to find food and stay safe.
Lead researcher Professor Glen Jeffery said: ‘Humans and almost all other mammals con’t do this as our lenses don’t let UV into the eye.’
Human beings are able to see light with wavelengths ranging from around 700nm, which corresponds to the colour red through all the colours of the rainbow in sequence to 400nm.
Professor Jeffery and his team tested the reindeer’s vision to see what wavelengths they could see and found that they can handle wavelengths down to around 350-320nm.