Tag Archives: eye colour

eyes change colour?


I didn’t realise how sophisticated reindeers are. It turns out they have two layers of fur to help them keep warm, are able to shrink the pads on their hooves to give then better grip, and can detect ultraviolet light which enables them too see in very dim light. And it also turns out that their eyes can change colour in winter so that their vision is more sensitive. Reindeers, like cats, have a reflective layer behind the retina (which is the inside of the eye ball where all the light-sensitive cells are) that helps them to see in dim light. This is why, if you see a cat at night, you might see the eyes shining; you are seeing light being reflected back at you from the cat’s tapetum lucidum (which is the technical term for the layer behind the retina). The light that shines back in most animals with this layer is golden but in reindeer it apparently shifts to blue in the winter. The shift to blue allows more light to be scattered and improves the vision of the animal.

The full paper can be read in the Proceedings of the Royal Society.

Eye colour and trust

According to a recent study eye colour plays a role in deciding how trustworthy others will think you are. Researchers simply asked a group of people to rate the trustworthiness of male and female faces. It was found that a majority of people found people with brown eyes to appear more trustworthy. This was true for both sexes but particularly so for men.


But it turns out that it is face shape that is more important and eye colour is a major factor because brown-eyed people tend to have certain facial characteristics. For the original story see here.