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Aquatic Turtles Shedding Scutes

The spine and expanded ribs of a turtle are fused through ossification to plates beneath the skin to form a bony shell. Both upper and lower sections of the shell have an outer layer of plates called “scutes” made primarily of keratin (as are hair, feathers, hooves, claws, horns and nails).  Scutes protect the shell from scrapes and bruises.

In most land turtles and tortoises, scutes remain on the shell for life, which causes the shell to thicken and protects it. Growth of the scutes occurs through the addition of keratin layers to the base of each scute.

For most water species, as the turtle grows, the epithelium, or thin layer of tissue between the scutes and the bony plates, produces a new scute beneath the old one that is a larger diameter than the one layered on top of it, allowing the shell to the turtle and its shell grow.  The old scutes shed or peel away to make way for the newer, larger scutes (see top of shell, or plastron, of Northern Map Turtle on right in photo). Basking in the sun helps turtles shed scutes by drying them and leaving them ready to fall off. Usually this happens without any assistance, though there are some species of turtles which do pull loose scutes off each other’s shells.

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6 responses

  1. Alice

    Growing is ‘so natural’ but really a miracle.

    May 31, 2021 at 8:12 am

  2. I never knew this! So interesting. Great photo.

    May 31, 2021 at 9:58 am

  3. Janice Kelly

    Hi Mary I should tell you more often how interesting and illuminating your posts are. Not only that but today I learned the word “scutes”. So fun. Thank you for all you do and for sharing your prodigious talent for nature and describing and photographing it so very well.

    Sent from my iPad


    May 31, 2021 at 10:14 am

  4. Yes! to the comments above.
    I’m learning, the older I get, how to simply feel grateful (rather than embarrassed or inadequate) when I discover something else I didn’t know, which happens for me every time I read a new post from you, Mary! I can’t claim that I’ll remember all the things I learn from your posts, but whether or not I can repeat them to someone else, or recall them sometime in the future, it sure is fun to take in all the interesting and often surprising new information you offer in your choices of what to show and tell us about.

    Every now and then I have noticed a turtle, sunning itself on a log, whose shell has looked like what you captured in this photo. Now I’ll know that I don’t need to worry about its health. And perhaps I’ll recall that I’m seeing it getting ready to shed “scutes.”

    By the way, I love how those two turtles are raising their heads right next to each other. It makes me curious about what will happen next? Are they enjoying each other’s proximity? Are they tuned in to each other? Or is each looking at something quite different from the other? How do turtles feel about each other, anyway (beyond mating)? Hmmm…
    Thank, yet again!!

    May 31, 2021 at 11:48 am

  5. Alice

    It seems like their back ‘digger legs’ are much bigger than the front ones, compared to painted turtles, who’s legs seem more equal in size.

    May 31, 2021 at 8:48 pm

  6. My goodness that is so fascinating! What a wonderful thing to read first thing in the morning! 🙂 ❤

    June 1, 2021 at 3:38 am

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