Some fish make sounds by grating their teeth and others, like some catfish, make sounds from their air-filled swim bladder.

U.S. Department of the Interior

March 25, 2011 | Categories: Resources

The U.S. Department of the Interior is a Cabinet-level agency that manages America’s vast natural and cultural resources. Secretary of Interior Ken Salazar heads our department, which employs 70,000 people, including expert scientists and resource-management professionals in eight technical bureaus.