Animal fats and oils are lipid materials derived from animals. Physically, oils are liquid at room temperature, and fats are solid. Chemically, both fats and oils are composed of triglycerides. Although many animal parts and secretions may yield oil, in commercial practice, oil is extracted primarily from rendered tissue fats obtained from livestock animals like pigs, chickens and cows. Dairy products also yield popular animal fat and oil products such as cheese, butter, and milk.