bear eating fish

anole eats insect

insects such as mosquitoes feeding on a host

tapeworm or hookworms living in host's gut

ticks and fleas that live in a host animal's fur - bite the animals and drink its blood

spider mites suck sugar from plants

The roots of the Owl Clover are partly parasitic on the roots of other desert wildflowers.

using a second organism for housing such as small mammal or bird that lives in holes in trees or orchids which live in trees

birds that live among cattle to eat the insects stirred up as they walk - egrets hunt for insects near a grazing animal's mouth

clownfish lives among the forest of tentacles of an anemone and is protected from potential predators

one animal attaching itself to another for transportation such as barnacles attach to shells or whales or a shrimp riding on a sea slugs

flowers and their pollinators (examples:  bees and hummingbirds gather nectar and spread pollen)

birds and mammals eat  berries and fruits while plant benefits by the dispersal of it seeds

coral reefs

algae and fungi > lichen - alga gets water and nutrients from the fungus and fungus gets food from the alga

cleaners eat insect pests from the skin of animals (ex: Egyptian plover cleans giraffes and buffaloes)

many herbivores such as cows, sheep, deer, horses and rabbits depend on bacteria that live in their stomachs to break down the plant material