Can red eared slider turtles drowned them self?

What I have to say is anecdotal and certainly not scientific! I hope it helps, but don't recommend that you rely on it!

We have a RES, known as "Mrs. Turtle" (we're not too creative with names!) who now lives in a pond in our back yard. She is now about 23 years old. We are in Central Florida, USA, and therefore in a sub-tropical environment. Mrs. Turtle stays in the pond year round, and, contrary to popular belief, it can get pretty cold around here in the winter time, even if only for a very few days at a time.

Our rule is that if the overnight temp is going to be 38F (5C) or less, Mrs. Turtle spends the night in a plastic box (a storage box, 24"x12"x12") in the garage with about 2 inches of her pond water in it. She settles down pretty quickly and sleeps with her feet out which makes her look pretty relaxed and comfortable.

The next day we will wait for a while for the sun to warm up the pond water for a while before taking her back out. We put her on one of her rocks, but within a few minutes she will slide into the water. After half an hour or so, she will climb out of the water and sit on a rock in the sun for several hours before going back into the water. She survives, but she is clearly not happy with the cold. It is also worth noting that she eats almost nothing when it is cold.

I believe tat she can tolerate cold for a short time as long as she can lie in the sun and warm up again fairly quickly. Extended periods of cold would probably give her serious or grievous problems because she would not eat. I would not like to find out!

I believe that in an artificially created environment it would be necessary to mimic the sub-tropical sun's effect and provide a suitable sunbathing area in order for a turtle like this to survive. I would not recommend extended periods of time in cold water for this type of turtle.