Association in which one individual takes advantage of another's food scraps without harming him. Eg: Shark and Remora, Lion and Hyena, Vulture and Man.
Shark and Remora Fish - The shark is recognized as the largest predator of the seas, ie the individual who normally occupies the apex of the food chain in the thalassocycle. Already the remora fish is small and unable to accomplish the feat of predatism. The remora fish lives then associated with the great shark, trapped in its womb through a suction cup (similar to an adhesive disc). While the shark finds a prey, shattering and devouring it, the remora waits patiently, limiting itself to eating only what the great shark did not want. After the meal, the remora fish tries to associate again with another hungry shark. For the remora the relation is beneficial, whereas for the shark it is totally neutral.
Leo and the hyena - Lions are big cats and fierce hunters typical of the African savannas. They live in packs and spend most of their day sleeping (about 20 hours, according to some ethologists). However, they are hunters, like sharks, at the apex of the food chain. Hyenas are small canids that also cluster in flocks, but live on the prowl of lions' clans. When lions are hunting, hyenas hide and wait for the whole group of cats to feed. Hyenas wait only for the moment when lions leave their prey carcasses to feed themselves.
Buzzard and the Man - The vulture (common names that vary by location but actually represent birds with the same lifestyle) is a man's dinner. Man is the being of nature that wastes the most food. Much of the solid waste in large cities is made up of organic materials that with low cost treatment would return to nature more rationally. The vulture is a large bird that uses exactly this waste of man in relation to the remains of food.