A true predator is one which kills and eats another organism. Whereas other types of predator all harm their prey in some way, this form results in their certain death. Predators may hunt actively for prey, or sit and wait for prey to approach within striking distance, as in ambush predators. Some predators kill large prey and dismember or chew it prior to eating it, such as a jaguar, while others may eat their (usually much smaller) prey whole, as does a bottlenose dolphin or any snake, or a duck or stork swallowing a frog. Some predation entails venom which subdues a prey creature before the predator ingests the prey by killing, which the box jellyfish does, or disabling it, found in the behavior of the cone shell. In some cases the venom, as in rattlesnakes and some spiders, contributes to the digestion of the prey item even before the predator begins eating. In other cases, the prey organism may die in the mouth or digestive system of the predator. Baleen whales, for example, eat millions of microscopic plankton at once, the prey being broken down well after entering the whale. Seed predation is another form of true predation, as seeds represent potential organisms. Predators of this classification need not eat prey entirely, for example some predators cannot digest bones, while others can. Some may merely eat only part of an organism, as in grazing (see below), but still consistently cause its direct death.
