Snakes have infamously poor eyesight, which is why they resort to sticking out their tongues all the time to get a sense of their surroundings. But the creatures may have a way to improve their vision in a pinch.
At least for one snake species, when the slitherer feels threatened, it controls the blood flow to its eyes to ensure that its sight is unobstructed, a new study found.
The research focused on the coachwhip snake (Masticophis flagellum), a thin, nonvenomous species that is found across the United States and Mexico and can range in color from brown to pink.
Like all other snakes and many other reptiles, coachwhip snakes don't have eyelids but rather a transparent scale called a spectacle that covers and protects the eye.
While examining the eye of a coachwhip snake, study researcher Kevin van Doorn, of the University of Waterloo in Canada, said he noticed a network of blood vessels in this see-through layer of skin.
Van Doran further investigated this feature. He found that the blood vessels constricted and expanded in a consistent cycle while the snakes were resting so that blood cells wouldn't pool up in front of the animals' eyes and obscure their already limited vision.