Human beings use animals for a wide variety of purposes, including research.
The approximately 260 million people in the United States keep about 60 million cats and about 52 million dogs as pets. Including birds and horses, the total of just these types of American pets comes to nearly 130 million. More than 5 billion animals are consumed each year as food. The U.S. Congress' Office of Technology Assessment estimates that between 17 and 22 million are used for biomedical research annually. In research, animals are used to learn more about biological systems and the illnesses that afflict human beings and other animals.