The average female grey nurse shark begins her pregnancy with about 40 embryos in her two uteruses. But it takes a year for the baby sharks to gestate, and by the time they’re ready to be born, there are only two left — one in each uterus. Why? Because by four months they’ve developed a full set of teeth, and the strongest begin cannibalizing the weaker ones.

http://www.collisiondetection.net/mt/archives/2006/09/so_apparently_s.html

Nothing to do with ” tech / web / geek / biz / internet / media” I realize.