Water bugs are fierce predators which stalk, capture and feed on aquatic invertebrates, snails, crustaceans, fish and amphibians. The largest species have also been found to capture and feed on baby turtles and water snakes. They often lie motionless at the bottom of a body of water, attached to various objects, where they wait for prey to come near. They then strike, injecting a powerful digestive saliva and sucking out the liquefied remains. Their bite is considered one of the most painful that can be inflicted by any insect; however, though excruciatingly painful, it is of no medical significance. Adults cannot breathe under water, and must surface periodically for air Occasionally when encountered by a larger predator, such as a human, they have been known to "play dead" and emit a fluid from their anus. Due to this they are assumed dead by humans only to later "come alive" with painful results