When humans sniff in order to smell something, we draw a quick puff of air into our nostrils and over chemoreceptors in our nasal cavity. But octopuses, butterflies, and other animals don't have noses like ours. Instead, they've evolved other, sometimes bizarre ways of sensing the world around them.

For instance, if you were to look closely at an Oregon shore crab (Hemigrapsus oregonensis), you wouldn't see anything resembling a nose. But that doesn't mean the creatures have no sense of smell.

"Smelling is really important to most animals, and crabs are no different," said Lindsay Waldrop, a postdoctoral researcher in biology at the University of North Carolina at Chapel Hill.

"We sniff with our sinuses, and crabs actually do the same