Caterpillar

I think this is a Black Swallowtail caterpillar. It looks ver similar to a Monarch Butterfly caterpillar ~ by design to avoid being eaten, since Monarch caterpillars are toxic or some such thing ~ but not quite the same. Two of them were munching away happily on a plant outside a bookstore in/on (I never know what to use with an island) Chincoteague we visited this afternoon.