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What a Snake’s Eyes Can Tell You

8-5-13  snake eyesYou can tell a lot about a snake just by looking at its eyes. Snakes that burrow underground usually have relatively small eyes compared to those that live above ground. The size of the eye and the shape of the pupil can often tell you if the snake is diurnal or nocturnal – typically diurnal snakes have comparatively small eyes with round pupils and nocturnal snakes have larger eyes with elliptical pupils. Both of these characteristics have to do with maximizing or minimizing the amount of light that enters the eyes. The larger the eye, the more light it can gather. The reason for the difference in pupil shape is that round pupils can close very tightly, to a pinpoint opening, shutting out bright sunlight very effectively. Elliptical pupils can open wider than round pupils, and consequently collect more light. (Photo is of a Common Gartersnake.)

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2 responses

  1. kpmcfarland

    “burrow”? I can’t really think of any snake that actually burrows. Is there one?

    August 25, 2013 at 7:46 pm

  2. Yes, I had reservations about using that term, but there actually ARE several species of burrowing snakes, not in New England, but in Mexico, Central America and Africa, including the Mexican Burrowing Python (Loxocemus bicolor ).

    August 25, 2013 at 8:48 pm

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