The vast majority of animals need to breed to reproduce. But a small subset of animals can have offspring without mating.

The process, called parthenogenesis, allows creatures from honey bees to rattlesnakes to have so-called “virgin births.”

Such events can shock those who care for the animals. Examples include a zebra shark named Leonie, housed with other female sharks at Australia’s Reef HQ Aquarium, who stunned her keepers in 2016 when three of her eggs hatched into living pups.

A few years earlier, at Louisville Zoo, a reticulated python named Thelma—who had never even seen a male python—laid six eggs that developed into healthy young snakes. And in 2006, at England’s Chester Zoo, a Komodo dragon named