Water skaters are true bugs; that is, insects that have piercing and sucking mouthparts, They are also fierce predators, feeding on any animal small enough to be subdued by the sharp stab of their stylet and the quick action of their digestive saliva. They lie in wait near the side of their pond, often using a trailing leaf as anchorage, until an insect falls on to the pond surface, making ripples as it struggles. Using very sensitive hairs on its legs, the bug detects these ripples and rapidly sculls off to get to the prey before any competing predators can do so. Once at close range, it uses its eyes to spot the prey before grabbing it with its raptorial front legs and piercing it with its mouthparts. Small prey may be sucked dry immediately but larger victims are often carried quickly to the sheltered pond's edge, to be dealt with at leisure.

The most specialised parts of a water skater are its legs. The middle pair act as the oars and the hind pair as rudders, so that the bug actually rows rapidly over the water. The ends of the middle legs push through the surface of the water, but two pairs have hairy pads that trap air and keep out water. The main body is also covered with water-repelling hairs, so the animal is easily supported on its stilt-like legs and can move about without breaking the surface film. Even in rough water it remains dry and safe, although it avoids these conditions whenever possible and cannot hunt unless ripples can form easily. After winter hibernation there is fierce competition for the rather erratic food resource, and many water skaters fly off in search of new ponds and lochs where competition will be less severe. Females will lay their eggs under water and the nymphs (larvae) emerge without wings, moulting five times before adulthood. Thus the smallest, most newly formed pond soon recruits its own population of water skaters.