14 DAY TRIAL // It looks like Edward Cullen is not the only one who switches eye color from time to time. On the contrary, reindeer living in the Arctic go through similar changes.
According to the new paper authored by researchers working with the Biotechnology and Biological Sciences Research Council, these herbivores have golden eyes during the summer months, and blue ones during winter.
Researchers theorize that reindeer evolved to change the color of their eyes from one season to the other so as to be able to better protect themselves against predators that would love nothing more than take them by surprise and turn them into a delicious lunch. EurekAlert tells us that, like many other animal species, reindeer living in the Arctic have a layer of tissue known as the tapetum lucidum (TL, for short) behind their retina. This layer serves to reflect light and thus make it easier for the animals to see during nighttime.
During summer, the TL is golden and much of the light that reaches it is bounced back through the retina, the same source details.
During winter, on the other hand, the TL turns blue, meaning that less light is reflected out of the eye and more of it reaches the animals' photoreceptors.
This translates into the fact that, despite the limited winter light, the reindeer are still able to spot predators and make a run for it before it is too late.
“This is the first time a color change of this kind has been shown in mammals. By changing the color of the TL in the eye reindeer have flexibility to cope better with the extreme differences between light levels in their habitat between seasons,” researcher Glen Jeffery with the University College London explains.
“This gives them an advantage when it comes to spotting predators, which could save their lives,” he further details.
Specialists say that, all things considered, shifts in the pressure within these herbivores' eyes are the ones to blame for this phenomenon.
More precisely, it is possible that, during winter, the pupil dilates and does not allow the fluid present in the eyeball to drain properly. This leads to the TL's being squeezed and thus forced to change color.