• Question: Komodo dragons can be pregnant without ever coming across a male dragon how come?

    Asked by wilsdog to Vicky on 20 Mar 2012.
    • Photo: Vicky Young

      Vicky Young answered on 20 Mar 2012:

      Hey Wilsdog!!

      I know some reptiles can do this but I didn’t know the Komodo dragon could. I had a check and it works the same was as the other reptiles who can. Its a little confusing because they are really different from humans as they don’t have X and Y chromosomes which determine what sex they are.

      Komodo dragons have the ZW chromosomes which determine sex. The female dragons can lay unfertilized eggs that have one copy of DNA that doubles (the DNA chromosomes double but the egg stays as one cell) in the egg to make two copies – just like it would have if a male dragon had fertilized them. She can only have male offspring though!!

      We think this happens as it allows a single female to enter an isolated ecological niche (such as an island) and produce male offspring which establishes a sexually reproducing population (via reproduction with her offspring that can result in both male and female young).

      Its cool!