Here's why:
* Endoskeleton: An internal skeleton made of bone, which provides support, structure, and protection for the body. This is the type of skeleton found in mammals, including ferrets.
* Exoskeleton: An external skeleton made of a hard, tough material like chitin. This is found in insects, crustaceans, and some other invertebrates.
Black-footed ferrets, being mammals, have a bony internal skeleton that allows them to move, breathe, and protect their vital organs.