A swimming robot that mimics the super-effective way that jellyfish move about underwater could soon be used to explore coral reefs and archaeological sites. Experts use a measure called the'cost of transport' to compare the movement efficiency of different species from across the animal kingdom. Such studies have show that nature's more efficient mover -- easily beating out running and flying animals and bony fish -- is the moon jellyfish, Aurelia aurita. These soft-bodied creatures move by squeezing their bodies in order to expel a jet of water that propels them forward. Inspired by this, engineers from Southampton and Edinburgh built a jet-driven robot that is around 10–50 times more efficient that its propeller-driven peers.