A team of scientists from Japan and England have built a computer that uses crabs as information carriers, to implement basic circuits of collision-based computing.
Researchers at Japan's Kobe University and the UK's University of the West of England, Bristol, found that when two swarms of soldier crabs collide, they merge and continue in a direction that is the sum of their velocities. This behaviour means that swarms of crabs can implement logical gates when placed in a geometrically constrained environment.
In their paper, “Robust Soldier Crab Ball Gate,” authors Yukio-Pegio Gunji, Yuta Nishiyama, and Andrew Adamatzky explain that swarms of soldier crabs herded through tunnels can form the AND, OR and NOT logic gates required to make a computer, with 0s and 1s represented by the absence or presence of a swarm.
Working initially with simulated swarms, the authors found that the OR gate, which combined one or two swarms into one, worked every time. However, the AND gate, which involves the combined swarm heading down one of three paths, was reportedly less reliable, according to New Scientist.
The experiment was then replicated using real soldier crabs. The swarms were placed at the entrances of the logic gates and persuaded to move by a shadow that fooled them into thinking a predatory bird was overhead. Results closely matched those of the simulation, suggesting that crab-powered computers are possible.
According to the authors of the report, no crabs were injured by the experiments. They were kept in comfortable condition, and after all experiments the crabs were released to their natural habitats.
The experiment builds on a previous model of unconventional computing, based on colliding billiard balls.
The paper's authors did not say whether public money was used to fund their experiments.