Asexual reproduction is common for animals like starfish, deep-sea worms, and stick insects, but among vertebrates, it's a rarity. A process called parthenogenesis allows some female animals to fertilize an egg with their own genetic material, producing offspring by "virgin birth." Scientists have assumed that vertebrates that usually reproduce sexually turn to parthenogenesis as a "hail Mary pass," a last-ditch effort at reproduction when there aren't enough mates to go around.
