In wintertime, reindeer utilize their blue eyes as a natural night-vision aid to locate food.

Animals’ eyes change color as the colder months approach in order to improve their UV sight, enabling them to easily spot the lichen that is essential for their survival.
According to scientists, Rudolph and his fellow reindeer do not rely solely on his famous red nose to navigate. They possess a unique form of night vision that helps them find food.
Researchers investigated why reindeer are the only animals whose eye color changes depending on the season. They found that this shifting color not only enhances visibility in snowy winters but also allows their eyes to transmit ultraviolet light.
This discovery raises more questions, as the reflection of the sun’s UV rays on the snow leads reindeer to receive twice as much UV light due to their advanced eyesight.
These remarkable eyesight capabilities enable reindeer to see clearly in the dark and locate food sources like lichen.
The study, conducted by Prof Nathaniel Dominy from Dartmouth College, Dr Catherine Hobaiter, and Prof Julie Harris from the University of St Andrews, delved into these findings.
Hobaiter commented, “Pale lichen on white snow is extremely difficult for us, as well as most mammals, to spot. However, for reindeer, the species they need to feed on stands out as dark patches against the highly reflective snowy landscape.”
Reindeer are known to depend on a specific type of lichen called Cladonia rangiferina or “reindeer moss” for their survival.
This lichen species, which grows like sponges across northern latitudes, is crucial for reindeer survival.
Prior to this study, it had been suggested that reindeer’s night vision evolved to help them find lichen. However, previous experiments failed to find substantial evidence.
According to Hobaiter, there are over 13,000 lichen species globally, but none of the reindeer’s food sources had been thoroughly tested until now.
She stated, “Scotland is an ideal location to solve this mystery since we have one of the most diverse lichen populations in the world. The Highlands alone house over 1,500 different species, and the Cairngorms are home to a local reindeer herd reintroduced after their extinction.”
The research team initiated their investigation in March within the Cairngorms mountain range in the eastern Highlands, searching for lichen beds.
The team used UV light to photograph various lichen beds and discovered that different species absorb or reflect light differently. They found that “reindeer moss” strongly absorbs UV light.
Dominy added, “If we put ourselves in their hooves, wandering in this white landscape, we would want a direct path to our food. Reindeer do not want to waste energy searching for food in a cold, barren environment. Spotting lichens from a distance gives them a significant advantage, allowing them to conserve calories during times of scarcity.”
This report contains contributions from PA Media.

Leave a Reply

Your email address will not be published. Required fields are marked *