Well, actually Thursday at Kingsford. When I took Raven out for a second walk in the park the next day, we took a different route, one that hugged the lakeshore, as much as it’s possible to hug the shore with steep ridges and valleys. For the most part, the ridges ran parallel to the shore, so it was easy enough to walk along the top without too much up-and-down effort.
It was while walking along here that I came across this on the forest floor; a turtle shell, long vacant of its owner. It was upturned, belly-up, nestled in the detritus of the forest floor. A few of the scutes, the hard material that covers the bony shell, were still attached in places. The scutes are made of keratin, much like our fingernails are. In theory, it may have been possible to identify the owner’s species with the help of these scutes, but there weren’t enough of them, and what was there wasn’t distinct enough, to be able to discern any pattern.
The plastron, the “belly” part of the shell, was still loosely attached when I picked it up and started carrying it home, but as I was trying to maneuver myself and a dog into a boat, I inadvertently applied a bit too much pressure to it and it popped in, separating cleanly at the “seams”, the points where the individual bone plates had grown together. It was only after I got it home that I noticed the upper shell itself was cracked, and it was only today as I sat down to write this, amazingly, that I noticed a huge gaping hole in the side of the shell. I can’t tell if this hole was created posthumously or was itself the cause of the turtle’s death, but it kind of looks like holes created by a bird with a sharp beak. The front of the plastron is also broken off, perhaps also an indication of predation.
Interestingly, removing the plastron makes it much easier to examine the inside of the shell, and you can see the backbone, fused to the shell, running its length. The shell itself is really just modified ribs, broadened and fused together to form a continuous surface. The plastron is the equivalent of our sternum, again modified to provide bony armor for the turtle’s underside. As such, it’s impossible to remove a turtle from its shell, the way you could remove a hermit crab from its shell – it would be like trying to remove us from our ribcage.