So some animals are called predators. They hunt and kill other animals for food. And the animals that are hunted and eaten by predators are called prey. But what about parasites? Parasites don't have to kill an animal in order to feed off it. In fact, parasites live on or inside a living animal, harming it, but not killing it immediately. The animal they live on and feed off is called the host. Fleees are an excellent example of a parasite. They live on the fur of an animal, such as a dog or a cat. And they bite and suck the blood while the animal is still alive, feeding itself and harming the dog or cat at the same time. Many parasites spread diseases such as malaria. The malaria parasite is called plasmodium. Humans are the host that plasmodium feeds on. Mosquitoes inject the plasmodium parasites into the bloodstream and in doing so they act as a vector for the disease. Spregem malaria is another organism without being affected by it. A parasite lives on or in another living organism called the host causing it harm.