Making Logic Gates Out Of Crabs

Building logic gates out of silicon is old hat, as is building them from discrete transistors, 555 chips, LEGO, and even gears. [Yukio-Pegio Gunji] and [Yuta Nishiyama] from Kobe University, along with [Andrew Adamatzky] from the aptly named Unconventional Computing Centre at the University of the West of England decided they needed a new way to build logic gates using crabs (PDF warning). Yes, the team successfully built functional logic gates using Mictyris guinotae, a species of soldier crab native to the South Seas.

The colonies of soldier crabs that inhabit the lagoons of Pacific atolls display a unique swarming behavior in their native habitat. When in a swarm of hundreds of individuals, the front of the swarm is driven by random turbulence in the group, while the back end of the swarm simply follows the leaders. Somehow, this is a successful evolutionary strategy, but it can also be exploited to build logic gates using only crabs.

The team constructed a Y-shaped maze for a pair of crabs to act as an OR gate. When two soldier crabs are placed at the top of the ‘Y’, they move forward until they meet and exit the maze through the output. This idea can be expanded to a slightly more complex AND gate, functionally identical to the electron-powered AND gate in a 7408 logic chip.

While the team has only made OR and AND gates – nothing functionally complete yet – there’s no reason to believe this crab-based system of computation couldn’t be expanded to a (very) basic calculator.

37 thoughts on “Making Logic Gates Out Of Crabs

      1. Yeah it kind of is. This is a university study. These guys probably just sucked up a bunch of money that could have went to someplace useful just so they can go and play with crabs. It would have been cheaper to go and get a hooker.

        1. You misunderstand the academic process. “Useful” is only an indirect goal. Studying how one formal system can be represented by another has been fundamental to our learning for longer than you’ve been around to question it.

  1. Relevant:

    Me 10:16 AM
    I wonder when crab technology will become sufficiently advanced that we can port our product to crab:

    Coworker 10:17 AM
    I think you’d need a whole crapload of crabs

    Me 10:17 AM
    Quick, to Joe’s Crab Shack

    Coworker 10:18 AM
    there might not be enough crabs in the chesapeake to make a crab-computer that could run gfx

    Me 10:18 AM
    True, I wonder if we can get better cycles per second by using larger crabs, like king crabs. Then use the small ones as a coprocessor

    Coworker 10:19 AM
    i think you’d probably want to at least start with large crabs
    that way you have a couple of die shrinks before crab’s law ruins your fun

    1. Well, you’ll note that the paper doesn’t include an acknowledgment of a sponsor, as would be customary if there was one….

      (I’d guess part of what led to this was “well, we had these crabs for this other research, see….”)

  2. I saw this on a “Gilligan’s Island” episode, the professor rigged it up to form a crude 4-bit computer to calculate trajectories for the “get’um home quick catapult”. But Ginger jiggled past, distracted the crabs, caused a bit-flow error, resulting in the wrong answer, ending with Gilligan landing in the volcano instead of on Fiji. Classic

  3. “While the team has only made OR and AND gates – nothing functionally complete yet – there’s no reason to believe this crab-based system of computation couldn’t be expanded to a (very) basic calculator.”

    All they need is a NOT gate and they have turing completeness with either NAND or NOR. Then they could solve anything.

    1. Actually, they’ve got “not(x) and y” and “not(y) and x”, on the two other exits to the AND gate. That may be enough by itself (I don’t recall for certain), but it’s definitely enough if you also provide an always-on stream of crabs to use for one of the inputs.

  4. For all you that think this is a waste of money you are very small minded. If you can make an army of crabs perform a calculation you can do the same thing with an army of cells. Maybe one day your smart phone will be nothing more then billions of amoebas. You won’t need batteries and you won’t need to charge it. Try to think out of the box.

  5. You have seen nothing yet. See for example:
    “Slime Mold Imitates the United States Interstate System”:

    And I am myself currently reading a book named
    “Information Processing in Social Insects”
    and really wondering what is this whining about “how damn hard the parallel programming is?”
    Well, these tiny critters have been doing it very well, for dozens, or even hundred millions of years!

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