A fish with humanoid teeth

July 6, 2009 • 2:52 pm

Courtesy of National Geographic, here is a photo of the pacu (Piaractus brachypomus), an Amazonian fish with a set of remarkably human-like choppers. It’s no surprise that they are herbivorous — eating mainly seeds — and that they can inflict a nasty bite.  They’re related to piranhas.

15 Pacu teeth 3.jpgPhoto from National Geographic website

29 thoughts on “A fish with humanoid teeth

  1. This reminds me a colossally stupid thing that Cornelius Hunter (one of the latest hacks to spew at the DI’s blog and UD) wrote:

    I debated one professor who claimed that both similarities and differences between species are evidence for evolution. Talk about having your cake and eat it too.


    I mean, imagine, similarities and differences both pointing to the process of, uh, evolution.

    Oh, except that evolution predicts exactly that, and a non-ignoramus would have discussed the differences between the similarities and the differences (like the nesting of similarities–themselves typically changed during evolution, but recognizable as basic shared characteristics). Not Hunter, though, whose entire modus operandi is to make strawmen to defeat, however usual that is for creationists.

    Convergences, like those fish teeth, then, are held to be impossible in evolution, no matter how stupid it is to claim that similar forms will not appear in related animals (we are fish, recognizably so in many of our bones, genes, and similar organs) in response to similar selective pressures. And never look at the typically very different origins of the “similar structures,” like our eye and the octopus eye.

    Anyway, this seemed a good time to laugh at how basically stupid about the theory these “experts” are.

    Glen Davidson

    1. “we are fish, recognizably so in many of our bones, genes, and similar organs”

      Hope so! Otherwise I’ve been wasting my time with all this zebrafish research.

  2. Someone get that fish some Colgate, a brush, mouthwash and some floss. My dentist would have him/her in every four months for a cleaning.

    The front 6 teeth (why 6?) look human, the back teeth(5 & 5?) – not so much.

  3. Hmm .. it might be cheaper for me to go on an Amazonian fishing trip than to go to the dentist. I hope I don’t need any replacement dentures any time soon.

  4. Ugh. That hits my irrational I’m totally squicked out because it crosses a boundary response. Rather like the well-known phenomenon among robotics researchers: if you make a robot that’s both too human-looking while also not quite human enough, people get the creeping willies. Sorry, I can’t remember the citation – it’s interesting, trust me.

    Super cool fish, though. In my head, he speaks in a Don Knotts voice and calls everyone “Pally.”

  5. True story. When I was younger we had a 200 gallon aquarium with a Pacu in it. The fish got too big for the tank and was destroying it and fighting with the other fish. Instead of filleting it, we let it go in the local quarry.

    A couple of months later, the local paper had a front page story of a “pirahna” that was caught by a local fisherman. The fish was kept in a tank at the local bait shop as an attraction.

      1. Because it was a quarry, it didn’t have any tributaries or runoff to natural sources, so we figured the environmental impact would be minimal if the fish even survived, especially because there was just one of them.

        We never fessed up (or took credit) to letting the fish go in the quarry, because it was against the law to loose foreign species.

  6. Interesting – re-looking at the teeth, they don’t seem to have bilateral symmetry. Perhaps they regenerate if lost in battle, and the little (or big?) ones are regenerated examples??

    James F – I had the same thought as you on first look.

  7. pretty awesome showing of convergent evolution. much like birds and bats and insects having wings, teeth structure is similar in these fish as it is with other mammalian organisms.

  8. Pacu fish is a tropical fish from the Serrasalminae family (serrated salmon family) which is an extension of the characids often referred to as tetras. Pacu fish, cousins to the piranha and known as “frugivores,” have human-like teeth that can crack nuts and fruits. The only difference is in the teeth structure which is sharp and pointed in case of piranhas and square-sharped in case of pacu fish. Also unlike piranhas, pacu fish are peaceful and don’t have an aggressive temperament.

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