Why does my puppy twitch and tremble while sleeping?

A puppy twitching in its sleep can have several causes. First, it may be chilled and shivering — warm it promptly with a hot-water bottle or heating pad.

Or the twitching may simply be from dreaming and usually fades quickly. It can also be a sign of canine distemper, a common and harmful puppy condition needing prompt treatment. Low blood sugar or low calcium also cause twitching. If the puppy twitches even when awake, take it to the vet promptly.