Slowing down for the season…   Leave a comment

As the evenings get cooler and cooler, I find myself slowing down a little, getting into a more mellow groove and getting ready to pull out some big fuzzy sweaters and spend more time indoors to stay warm. Of course, our turtles are all getting ready for the cooler weather too! As the temperature drops, turtles across Ontario are moving towards their hibernation sites, spots which they know will be safe to use over the winter. What makes a perfect hibernation site for a turtle? Let’s just say it’s not what I’m looking for in the winter months! Turtles spend the whole winter under the water, often under ice. Because hibernating turtles don’t want to become scaly ice-cubes, they need to find sites which won’t freeze solidly to the bottom. They also need to get enough oxygen out of the chilly water to get them through the winter (since they won’t be able to come up to breath once the ice forms on top of their wetlands). Our turtles get through the winter by slowing down their metabolism (although they can still move if they need to) and exchanging oxygen across the lining of their cloaca – basically, they breath through their bums! In the case of Eastern Musk turtles (aka. Stinkpots), oxygen is also exchanged underwater across the surface of the tongue. However they get oxygen from the water, they need a site with water containing enough oxygen to get them through the long cold months ahead.

A Blandings Turtle basking on a grassy bank after emerging from a long, cold hibernation. (Photo: C. Davy)

Some turtles need more oxygen than others – recent studies show that Blandings turtles, for example, can tolerate winters in low-oxygen water which could not support some other species. But all overwintering animals need at least some oxygen to get them through. This is why changes in the water level of wetlands during the winter can be dangerous for overwintering wildlife. If a previously deep area (with lots of oxygen, and with lots of water under the ice) suddenly become shallow, for example, due to an ice jam or the bursting of a dam, turtles hibernating in that area may not have the temperatures or oxygen level they need to get through the winter. By the time things freeze over, it can be difficult for turtles to move to a different site. So the decisions they are making right now about where to spend the winter can literally be a matter of life and death!

– Christina Davy

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Posted September 23, 2011 by thinkingturtles in Uncategorized

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