Archaeozoology is the study of animals in archaeological contexts. These include all the organic remains left in the soil after the death and decay of animals but also the representation of animals in rock art and on portable materials. Zooarchaeology is a comparable term but differs in that the primary reason for study of the animals is archaeological rather than zoological. These are mostly bones and teeth. Sometimes hair, skin or other body parts are found and can be studied. Archeaozoology also studies the animals' effect on the environment and their relationships with humans. The people who study archaeozoology are called archaeozoologists. Their training can be as biologists or archaeologists.