Lazy Weekend (more photos of Peanut)
It always amazes me how small of a ball dogs can curl up into. It never seemed possible (not to mention comfortable) for a dog to curl up like that. Never one to let things go unresearched, I hit the net. As it turns out it's a legacy thing from before dogs were domesticated and given a warm safe place to sleep. The best way for a dog to sleep was curled up because it kept their extremities (paws, nose, etc) covered by their body for warmth, and it presents only hard bone to anything that would attack the dog. The downside (and this is why you don't always see your dog curled like this) is that the dog can not reach REM sleep because it needs to keep it's muscles tensed to keep that position.