It's a made-for-tabloid headline: "Scientists Confirm Second-Ever Case of Virgin Birth by Shark." But there's no alien Elvis here. The story is based on a study in the Journal of Fish Biology. Researchers found that a female blacktip shark named Tidbit became pregnant at a Virginia aquarium, despite not having a male shark in her tank for eight years. Sadly, she did not live to see her miracle pups. Her pregnancy was only discovered during an autopsy.