In the animal kingdom, pregnancy rarely follows the rules, with many species being pregnant for a year or more.

The frilled shark has a unique mode of live-bearing and is thought to exhibit a long gestation time of no less than three years. Credit must be given to the creator.

While giving birth to live young is a trait that most people associate with mammals, this reproductive mode—also known as viviparity—has evolved over 150 separate times among vertebrates, including ...

The frilled shark, a living fossil from the Cretaceous period, boasts primitive features like an eel-like body and frilled gill slits. This deep-sea predator, rarely seen, offers insights into ...