Animal Behavior

General Description

Symbiosis is an interaction between two different organisms living in close physical association. The three types of symbiosis are mutualism, commensalism, and parasitism.


Mutualism is the way two organisms of different species exist in a relationship in which both benefit from each other. One example of a mutualistic relationship is that of the oxpecker (a kind of bird) and the rhinoceros or zebra. Oxpeckers get food and the beasts get pest control.


Commensalism is a type of relationship where one of the organisms benefits greatly from the symbiosis. The other is neither nor harmed from the relationship. One example of this is the relationship between barnacles and whales. The barnacle is a type a crustacean that can't move on it's own, so it attaches to the whale for transportation. When the whale moves, the barnacles catch hold of floating plankton and other food. They get nutrition and transportation, but do not harm the whale.


Parasitism is a relationship in which one organism (parasite), lives off of and harms another organism (host). One example is the relationship between a tapeworm (parasite), and a human (host). The tapeworm attaches to the inner wall of the human's intestines and feeds off of the food (nutrients) that is being digested. This starves the human (host) of the nutrients it needs to survive. If not taken care, the parasite can kill the host.

Other Examples of Symbiosis