A 6-foot-long electric eel is basically a 6-inch fish attached to a 5-1/2-foot cattle prod, researchers say. The long tail is packed with special cells that pump electricity without shocking the fish.
Mark Newman/Getty Images/Lonely Planet Image
A curious cuttlefish stares back at the camera from inside The Smithsonian's National Zoo Invertebrate Exhibit. The exhibit, home to dozens of small aquatic and terrestrial species without backbones, closed on Sunday.
Meghan Murphy/Smithsonian's National Zoo
A mountain lion known as P-22 was recaptured in March by National Park Service biologists and treated for mange. Wildlife officials believe the cougar's ill health is the result of exposure to rat poison.
National Park Service
DNA from these crab plovers, collected in Djibouti, Africa, should help scientists figure out how the unusual species fits into the family tree, says the Smithsonian's Helen James.