Jet-darters are meat eaters, but they do not hunt. Instead they feed off of animals that are already dead. They are therefore scavengers.
Jet-darters are too fast to be hunted by most animals on Darwin IV, but one spieces does kill jet-darters. A spieces of fungus which sends electricity at anything that gets too close, killing them. The Electrophytes! It is also hunted by the Finned Snapper.
Jet-darters move through a kind of biological jet propulsion, not unlike the Skewer, but differ by having a ramjet-style function composed of rotating bone and cartilage, which is capable of launching them up to speeds of 64 kilometers per hour (40 miles per hour). When at rest, they use three legs in a tripod arrangement, which otherwise fold up during flight.