Anthrozoology is an interdisciplinary field that examines all aspects of human interaction with nonhuman animals. A prominent concern in the field is with ethical questions about how humans treat other animals, and how and why ethics vary across societies and change over time. A number of anthrozoologists are interested in the biological and ecological nature of nonhuman animals, how macrostructural human–animal relationships affect socioecological evolution, and in individual-level interactions between human and other animals. Other scholars focus on how the symbolic meanings of animals are socially constructed and how those meanings are used in discourses about humans, such as around inequalities of race and class.