Finding Nemo

WARNING – stop here if you love Nemo, or are young, either physically or at heart.

If you’ve ever watched Finding Nemo, you know it’s a cinematic classic; a family-friendly tale of adventure in the deep sea. For those without a childhood, here’s the 5-second plot: Marvin, papa clownfish, and his young son Nemo are the sole survivors of a terrible barracuda attack that kills the rest of their family. Cue timeskip. Nemo, in the midst of adolescent angst, gets scooped up by a fish-fanatic dentist, and Marvin spends the next 2 hours tracking him down, having many Pixar-style adventures along the way. A heartwarming story.

Until biology enters the picture.

It turns out that your garden-variety clownfish – Amphiprioninae – is a sequential hermaphrodite. This means that a clownfish is born male, and as they mature, it becomes female. Clownfish schools also have a strict matriarchal hierarchy – only the biggest, baddest, of the bunch is female, and the rest remain male. Only the biggest male has the privilege of breeding; the rest just, well, float around. These males are stuck in a developmental impasse – when the female dies, the alpha male develops into a female, and everyone else moves up a rung in the ladder. Really, quite remarkable biology.

Until you watch Finding Nemo again. Then you realize, as my 12-year-old self did, that Marvin, papa clownfish, by virtue of being the biggest survivor, is now mama clownfish, and Nemo, by default, is now papa clownfish. Marvin is tracking down Nemo to, well, clown around. Did Pixar know about this? I’m not sure, but it sure smells fishy.