Naturespeak A naturalist's view of the world

May 30, 2009

High & Mighty

Filed under: Uncategorized — wykes @ 11:09 pm

Most turtles are sun worshippers. They make it a habit to reap a daily harvest of solar energy. The closer these poikilothermic (cold-blooded) beasts can get to Old Sol, the better. For an aquatic turtle “getting close” usually means climbing the gentle slope of a rock or scrambling the low incline of a stump in order to intercept the life-giving rays. Sometimes it even means climbing on top of their fellow shell mates in a game of one-upmanship. Because swimming appendages do not make for good climbing tools, what ever height is obtained is normally not all that lofty.  There is, of course, always an exception and I’d like you to meet him (see above).

The exceptional example pictured above is a Map turtle (see close up here). These turtles are so named because of the wavy road-like lines on their shell, although they are equally well marked with yellow highways on their head, neck ,and legs.  As a species they tend to be mountain climbers, but this particular turtle was pushing the atmospheric limits when I encountered him late yesterday afternoon. Three of his four legs were dangling freely into space and the center of his plastron was squarely set upon the root tip. There was nothing but warm dry air surrounding this turtle. Normally these fellows are quite skiddish and will tumble into the water at the slightest provocation so I snuck up behind a tree and snapped off a view before this remarkable scene was lost. 

There are many reasons for a turtle to bask, and I reflected on those reasons as I watched Sir Edmund Mappery.  The primary reason is to raise the internal body temperature to the required 28 degrees C, but that thermal rise achieves many other positive results. High temperature promotes good digestion, for instance,  and accelerates egg development in females. The activity also aides in the synthesis of Vitamen D. One of the less appreciated benefits of drying is to discourage parasites and algae growth – a good blow dry to shed nasty leeches.

All this is fine and good, but a basking turtle is not all that exciting to watch. Even the presence of an additional two turtles to the branch (see below) failed to notch up the personal excitement level. Sensing the opportunity to get a great shot of a diving turtle, I focused in on my subject and started to wave my hands about to see if I could make him take the plunge. Despite my best efforts, the turtle sat there as if glued to his post. I stepped out from behind the tree, expecting him to bolt, but he remained.

I walked down the shore and gesticulated, but he showed no desire to move what-so-ever even though he was only about 25 feet away. I was getting warmed up in the late day sun, as a matter of fact. Even tossing a few pebbles into the water failed to elicit any reaction.

About this time a family walked up the shoreline and I flagged them down. “See that turtle over there?” I asked. “I’m trying to get him to jump and I need your help. Could you walk back over that way and wave your hands?”  Again I focused in and waited. They agreed and performed as requested but turtle remained stoic. The scene in my view finder remained a still life. 

I was ready to give up at this point, but the dad picked up a large boulder and instructed his son to do the same. “We’ll give you your National Geographic moment,” he said proudly. “Just tell us when.”  For a moment I felt a twinge of guilt come over me as I realized that I was about to encourage an act of wildlife harassment. I quickly overcame this feeling, however, and calmly gave the go-ahead. There was some warm-blooded pride to uphold.

The pair gave the rocks a mighty heave and they both landed only a few feet in front of  the high and mighty turtle. Tremendous plumes of spray shot into the air as if two depth charges were set off. My viewfinder temporarily filled with white and I expected to see an empty perch when it subsided. The shock waves radiated out and rolled across the water. Even though the act sent his two other log mates packing, the king of the root remained in exactly the same position. He looked directly at me (see below) and smiled.  Apparently, basking also produces extreme self confidence. We all gave up and left.

Today I returned to the spot just to make sure that the turtle wasn’t actually glued to the root. Indeed, he was there again, but was re-positioned at a point just below the tip. As I watched, a cloud shadow passed over the waterway and the turtle  frantically plunged into the water like a scared rabbit.

1 Comment »

  1. One more reason for basking… the heat helps turtles to shed their old scutes to make room for fresh ones. The scutes literally dry up and either fall off eventually, or are forced off when a turtle, much like a bear scratching its back against the bark on a tree, rubs its shell against any hard, resistant surface in an attempt to knock off the offending – probably somewhat itchy-feeling – scutes.

    At least, this is what I have observed of my painted turtle in his little aquarium world. Sometimes, I will pull the scutes off for him!

    Comment by Kathy — June 1, 2009 @ 3:43 pm

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