What is it about zoo residents?  Is it because they're cooped up all day with nothing better to do? Is it because they lack the appropriate clothing for their unusual size and shape? Is there no laundry service? Whatever the reason, whenever you go to the zoo, what can you be sure to see? Heinies, and plenty of 'em. From demure to bodacious, Ayun Halliday and Dan Santat are finally willing to show us the true appeal of the zoo--There are always heinies, and lots of 'em.