Scientists are baffled after spotting a female zebra shark in an aquarium having given "virgin birth" to pups - meaning she reproduced without mating with a male.
The process, called parthenogenesis, allows some female animals to fertilise an egg with their own genetic material, and produce offspring.
Although asexual reproduction is common for animals like starfish, deep-sea worms, and stick insects, it is a rarity among vertebrates.
