Baby sand tiger shark eat each other in the womb until only one is born.
Means, When there are 2 or more babies in the stomach of a sand tiger shark, then they fight among themselves and the one who survives in it is born.
They eat each other in the womb as a paternity strategy. Recently DNA testing revealed that the mystery of baby shark cannibalism is due to embryos from different fathers competing to be born. If there are two embryos with the same father, they will eat all the others so they can both live, which strengthens their bloodline.