A Bonnethead shark at the Aquarium of the Pacific in Long Beach, Calif., on April 26, 2012.
Think it would be hard getting a date if you were a hammerhead shark—easily the homeliest fish in the seas? Imagine being a species of hammerhead called the shovelhead, which doubles down on ugly in just the way its name suggests. In 2007, researchers discovered that a female shovelhead living in captivity that had never been exposed to a male got around the lonely-on-Saturday-night problem by joining the group of species that have mastered the act of virgin birth. The shovelhead managed this feat through automictic parthenogenesis—which is different from the marmorkrebs’ apomictic—producing a full set of chromosomes in the egg by doubling the mother’s genetic material, rather than getting half from a male.