I found this Turtle shell a couple of days ago while hiking the Ouachita National Forest here in Arkansas. I find shells like this more often than I care to. I always wonder how these turtles died and I always hope it was from old age. I found this one on its back, but that does not mean that it died that way. An animal could have moved it after it died.
Turtle Shell Facts
The turtle shell is a highly complicated shield for the ventral and dorsal parts of turtles, tortoises and terrapins (all classified as “turtles” by zoologists), completely enclosing all the vital organs of the turtle and in some cases even the head. It is constructed of modified bony elements such as the ribs, parts of the pelvis and other bones found in most reptiles. The bone of the shell consists of both skeletal and dermal bone, showing that the complete enclosure of the shell probably evolved by including dermal armor into the rib cage. (Wikipedia)
Turtle shells have three main parts: the upper or top piece (carapace); the bottom (plastron); and the bridge that fuses the upper and lower pieces together.
A turtle’s shell is attached to their body. Turtles do not look for a bigger shell as they get bigger, instead the shell grows with the turtle.
The shell is composed of hard, bone plates covered by scutes. The scutes are made of keratin, the primary substance in hair, nails and hooves of other animals.