How can aquatic turtles stay under water so long? I’m watching one in Crystal Lake and she (?) is staying on the bottom of the lake for a long time. I’ve been watching her for a while and I’ve decided to call her Jacqueline.
I was going to go kayaking but then I saw the turtle next to the dock and didn’t want to disturb her. I sat down on the dock and began watching. I’m starting to think this is pretty boring. How can I just sit here staring at a ten-inch circle snuggled into a patch of seaweed? In truth, the lake environment is neither bored nor boring. It is my problem that I’m losing interest. I remember a comment I made at a study group a few days ago: Ask questions of the material and your curiosity will guide you. The question that comes to my mind now is about turtle respiration. How do they do it? The question gives me a time frame: Watch Jacqueline until she comes up for air.
She is a snapping turtle with a blunt, diamond-shaped head and a shell covered with algae. The algae looks like a fur coat and I want to pet it. (Snappers came by their name for a reason, so this would not be wise.) A sapphire dragonfly zips by and reminds me to pay attention. I look up and see a bald eagle flying toward me across the lake, making high piercing calls before landing in a pine tree.
The book I’m reading lately, One Square Inch of Silence by Gordon Hempton, comes to mind and prompts me to listen more carefully. Hempton is trying to help preserve natural quiet in a square inch (and beyond) of the Olympic National Park in Washington state, and elsewhere. He is a professional listener and recorder of sound who is troubled by the increasing pervasiveness of man-made noises. I let my ears lead me and notice that I can hear vehicle traffic from time to time. Someone across the lake is cutting wood and then hammering it. A flag flaps in the breeze and children splash into the water. The cars from the county road could be considered noise pollution, but the rest doesn’t bother me.
Still, the turtle hasn’t come to the surface. I think of my yoga teacher, Laura, saying “If you haven’t breathed lately, now would be a good time to do so.” Does it make me anxious to see an oxygen-dependent being under water for more than twenty minutes? Oddly, it gives me a sense of peace, of being still and grounded. I take a breath. After another ten minutes or so, I see the tiny tip of Jacqueline’s nose break the surface and bubble a bit, breathing with the least effort imaginable before she snuggles back into her seaweed bed. It’s time to go kayaking.
Later, checking the Encyclopedia of Earth online, I find out that snappers and some other types of turtles use the soft tissue in their mouths like gills, extracting oxygen from the water. That’s how they obtain enough air to stay alive while hibernating for months at the bottom of lakes. It is not enough air for active daily life, but it is something. My questioning mind is somewhat satisfied, though I am still amazed at Jacqueline’s ability to stay submerged for so long. I’m just glad that my turtle neighbor, with her ten round inches, gave me an excuse to be quiet, watch, and listen for the duration of a breath.
I believe another large factor in aquatic reptiles ability to remain submerged is their relatively slow ecto-thermic metabolism. They don’t have to burn fuel to keep up their body temperature, and thus don’t need as much of the oxygen that enables that process.
Thanks, Alec, that makes sense. So we warm-blooded critters require more oxygen?
Yep, and more food too – large snakes can routinely go months between meals because they rely on ambient heat to keep their body temp up.
What a great read Barbara. I felt like I was right there. Thx for including me