A stowaway on Noah's Ark Book

Achbar the mouse hears a kindly old man tell the animals of the world that there will be a great flood, and that he has built an ark big enough for two of each kind of animal to ride out the storm. But by the time Achbar works his way through the tangle of paws and hooves, two other mice have already been selected. Achbar is terrified and does not want to be left behind! His survival instincts tell him to stow away. But will he be discovered by the old man--and will they ever see dry land again?