They say stare into the abyss and the abyss stares back, and no truer could that be than when you shine your light into a field or garden at night. You see, all those little dots of light reflecting back at you? There's a good chance they're spider eyes. The rest of this article is behind a paywall. Please sign in or subscribe to access the full content.

Safe in the shadows, they can scuttle among the grass unseen (by human eyes, at least) but shine a light and their peepers glow light cat’s eyes. Why? Because of a little thing called the tapetum lucidum.

Tapetum lucidum

The tapetum lucidum is why cats’ eyes glow. It’s also why great white sharks' eyes do, too. Oh, and it explains why reindeer eyes turn blue in winter . Clever little thing, the tapetum lucidum .

So, what is it? At

See Full Page