It’s the Halloween season — the perfect time of year to be caught off-guard by a pair of glowing green eyes.
But if you happened to be spooked by a harmless black kitty in the still of the night, take a minute observe the glow — it’s actually a wonder of nature, according to wildlife expert Frank Ritcey.
“Eyes in the world of animals are incredible in their diversity,” he said on CBC’s North by Northwest. “It’s worthy of so much research.”
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The iconic phenomenon is known as ‘eye-shine’, and it can be seen all over the animal kingdom.
But what causes it?
In some animals’ eyes, there’s a structure called tapetum lucidum — a layer of tissue meant to increase the amount light shining on the creature’s retina, contributing to superior night vision.
“It is present in many animals that are nocturnal in their habits,” said Ritcey.”And depending upon the species this tapetum lucidumreflects light differently.”
The varying reflections actually produce different colours in the eyes of different animals.
In fact, one of the best ways to spot a poor-will (a small nocturnal bird) is to shine a flashlight into its woodland habitat at night. When the light catches its eyes, you’ll find off a pair of eerie, blood red eyes staring back at you, says Ritcey.
Meanwhile, nighthawks — a closely related specie — gives off more of a yellow glow.
“The variation can be seen across species and in some cases individuals within a species can display different eye-shine,” he said.
It’s all related to diet — certain minerals will enable the creatures to reflect light differently and Ritcey says it’s natural wonders like eye-shine that draws him to study wildlife.
“That’s what keeps me so interested in nature, it seems that once you get one question answered, there are 10 new ones.”
With files from CBC’s North by Northwest
To listen to the full interview, click on the audio labelled: Wildlife expert: The fascinating adaptation of animal eyes