Sharks are older than dinosaurs, but they're still evolving. One of their amazing evolutionary developments? Walking. Epaulette sharks, named for their military-like coloring, have been walking for at least 9 million years. Their unique adaptation is perfect for hunting food in reefs, as is their ability to go long periods without oxygen. Scientists this month published new findings about them, including the discovery of four new species, in the journal Marine and Freshwater Research.