And you thought YOUR siblings were tough

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.

  1 comment for “And you thought YOUR siblings were tough

  1. Mike
    September 7, 2006 at 4:05 pm

    To paraphrase the late Steve Irwin:

    Crikey! That sounds very dangerous!

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