The crocodile shark is aplacental viviparous and typically gives birth to litters of four, two pups to each uterus. The gestation period is unknown but believed to be long. The embryos have yolk sacs at 3–4 cm (1.2–1.6 in) long; once the yolk sac is fully absorbed they become oophagous: the mother produces large numbers of thin-walled egg capsules that contain 2–9 eggs each, which are then consumed by the unborn embryos. The abdomens of the embryos become characteristically distended with ingested yolk material, which can make up a quarter of the embryo's total weight. It is unclear how two crocodile shark fetuses manage to share a single uterus, when in some other oophagous mackerel sharks such as the sand tiger shark ("Carcharias taurus"), only one fetus survives in each uterus. The pups are born at approximately 40 cm (16 in) long; males attain maturity at 74–110 cm (29–43 in) and females at 89–102 cm (35–40 in). There is no defined reproductive season.