John Heinz National Wildlife Refuge

I found this Painted Turtle basking in the sun at the John Heinz National Wildlife Refuge in Philadelphia. That's right, Philadelphia! This is actually the largest remaining freshwater tidal marsh in the entire state of Pennsylvania, and it is located in the City of Philadelphia.

At one time, this marsh extended over 5700 acres. As the city grew, the marsh was drained and filled. It was finally saved from complete destruction in 1972, with only 200 acres left. Today, these 200 acres are home to many Painted Turtles (and other creatures).

An interesting thing I learned about Painted Turtles is that when they hibernate for the winter, they bury themselves up to 3 feet deep in the mud at the bottom of a pond or stream. This keeps them just above freezing temperature, but of course does not allow them to breathe air. Painted Turtles have evolved the amazing ability to survive for up to 4 months with no oxygen!

The trick to "holding your breath" for so long is to avoid the buildup of toxic lactic acid in your blood. Since the Painted Turtle is hibernating, its production of lactic acid is very low to begin with.

But then something very interesting happens - the turtle releases calcium carbonate and magnesium carbonate from its shell into its blood stream, to buffer the lactic acid. It also takes up lactic acid from its blood into its shell with the same effect. Voila, he can hold his breath for 4 months!

We saw various other animals at the refuge including deer, fish, frogs, birds and insects. The only other halfway decent photo I got was this one of an oddly colored dragonfly. It is known as a Low-flying Amber-wing.


If you are ever in Philly, check out the John Heinz National Wildlife Refuge. It is nearby Fort Mifflin which I previously posted about.