Maybe he wanted to indulge in a few holiday snaps, or maybe he's simply a kleptomaniac crab (a krabtomaniac?), but either way, this camera's owner was very lucky to hang onto it.
Then again, if someone left a camera outside your front door to record you, would you just leave it sitting there?
(Also, crabs up close are terrifying. If they ever mutate and become giant, we're on the first rocket into space. Yes, even after having seen Gravity.)