Female Shark Gets Pregnant on Her Own, No Male Required

A female blacktip shark in a Virginia aquarium got pregnant despite the fact that no male blacktip sharks shared her tank in her eight years of residency, researchers say. This is the second documented case of asexual reproduction, or parthenogenesis, among sharks; the first example of a shark "virgin birth" occurred with a hammerhead shark in a Nebraska zoo. The new findings suggest that the previous event wasn't a marine miracle.