Naturespeak A naturalist's view of the world

May 25, 2007

Road Map Turtle

Filed under: Uncategorized — wykes @ 11:19 pm

  The lowly Map Turtle is rarely on anybody’s turtle list. It seems that Painted Turtles and “Snappers” get all the attention.  I’m not sure why that is, because Map Turtles are very common (especially along Lake Erie), get really big (a foot or more in shell length) and have a lot to offer the curious eye.  

  I’d like you to take a look at a photo of one of these turtles here and then come back for closer look.  The “roadmap” appearance of the shell and body ornamentation along with the “keeled” shell ridge are two distinctive traits of this species. You’ll also see that the head is boldly patterned with two yellow eye-spots behind the real eyes and that the mouth is equipped with a powerful beak. Now, let’s take look at two unappreciated features.

   I spotted one of these well-named turtles contemplating a road crossing the other day. Fearing that his endeavor would surely end in disaster, I turned my car around and picked him up.  It was a handsome, and testy, little male with a 4.5 inch long shell.  He greeted my act of kindness with an open mouth and a willingness to remove a piece of my flesh. The males of the species have relatively small heads, but their bite is sufficient to crush snails – their primary diet. The gals, on the other hand, have massive heads with broad jaws that can crack open clam shells, so the female bite requires more respect. 

  I was struck by the marvelously adapted hind feet and plump slug-like tail of my little road kill inclined reptile. I drew a few of these features for you to look at because these are the kind of things that don’t show up in photographs.  It’s understandable that nature photos don’t normally depict the south end of northbound turtles, but regrettable. 

  The paddle-like hind feet evoke images of a sea turtle or seal flipper (look here and here). The individual toes are lost in the overall aquatic propulsion design and the webbing has taken over. What we have here is essentially a fin and thus the reason that Map Turtles are swimmers par excellence. When these turtles come out onto logs to bask in the sun, they often take on a spread eagle pose and stick these feet out as far as they will go. Like tree leaves, the paddle feet absorb much needed heat from the sun.

  Not quite as remarkable, but noteworthy, is the long fat tail that identifies my turtle as a male (take a look).  It looks like a plump green and yellow slug peeking out from under the jagged rear border of the shell. Over 20% of the overall body length is accounted for by this brightly striped appendage. This is one of nature’s great tails.

  For the sake of science, I should remind you that the male’s long tail is thing of necessity.  The anal opening is located near the tip so that it can be extended around the shell of the much larger female during mating

 Appreciation of nature often stems from attention to de-tails such as these and leads to the de- feet of ignorance

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