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Green Frogs’ Coloring

7-13-16  turquoise green frog 030Despite their name, Green Frogs are not always green.  They can be brown or tan, as well as many shades of green.  Usually Green Frogs in the Northeast are a combination of these colors, but occasionally one sees greenish-blue coloring on a Green Frog.  An understanding of what causes a frog’s green color sheds light on why sometimes all or part of a Green Frog may be close to turquoise than green.

Basically there are three types of pigment cells (chromatophores) which stack up on top of each other in a frog’s skin.  The bottom layer (melanophores) of pigment cells contain melanin, a pigment that appears dark brown or black.  On top of these cells are iridopores, which reflect light off the surface of crystals inside the cells.  When light hits these cells, they produce a silvery iridescent reflection in frogs, as well as other amphibians, fish and invertebrates. In most green frogs, sunlight penetrates through the skin to the little mirrors in the iridophores. The light that reflects back is blue. The blue light travels up to the top layer of cells called xanthophores, which often contain yellowish pigments. The light that filters through the top cells appears green to the human eye.

The pictured turquoise-headed Green Frog most likely lacks some xanthophores in the skin on its head, and thus we see reflected blue light there.

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3 responses

  1. Marilyn

    Color is fascinating. One year I had a blue frog in my pond. I’d never seen that before.

    August 17, 2016 at 8:26 am

  2. Hi Mary… Great explanation on a frog’s pigment cells effecting their color.
    I have left you an attachment on a turquoise colored body of a green frog with it’s green legs in your mail box shot down at my pond in June, 2011…

    Thanks,
    Bill…

    August 17, 2016 at 10:00 am

  3. So interesting! And complicated. 😉

    August 17, 2016 at 9:15 pm

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