Did you know some sharks can reproduce without having to mate first?

Some captive female sharks have been known to reproduce without the aid of a male, essentially cloning themselves. In 2001, a female hammerhead shark gave birth in the Henry Doorly Zoo in Nebraska without mating with a male, taking researchers by surprise. It's an example of parthenogenesis, wherein embryos can be created without external fertilisation, and has been seen in all types of animals except for mammals.