The mouse has it made.

He gets to run around on four legs. Balance advantage.

He gets to eat cheese all the time. Food luxury advantage.

If he's not running away from cats, he's probably eating cheese or sleeping. Lazy advantage.

He has a hole, where the giants can't get at him. Seclusion advantage.

If he can't get back to his hole, he can probably make a new one, or even hide under a couch. Evasion advantage.

Today, I'd like to be a mouse. A white one, with red eyes. The kind that squints up at you, but really in a smug, wild sort of non-tame way.