That's the sales gimmick that you didn't see.... You need to buy a whole army of these things in order to keep logistics running correctly..
One dog to bite.
One dog to change the battery of the dog that bites.
One dog to insert extra batteries into charger.
One dog to store and retrieve batteries from battery shelf.
One untitled dog to piss everyone off ( wink goes out to everyone's favourite goose).
Anyway you get the idea.
I hate Boston Dynamics, they are just so damned good at what they do, it must be fun being on their team.... certainly more fun than working in my industry.....