Mammary glands are specialized organs found in mammals, responsible for producing milk to nourish infants. These glands are composed of glandular tissue and are located in the breasts of females. During pregnancy and after childbirth, hormonal changes stimulate the development of these glands, allowing them to produce milk through a process called lactation. In addition to their role in feeding infants, mammary glands also play a part in the reproductive process. The presence of mammary glands is a defining characteristic of the class Mammalia, which includes animals like humans, dogs, and whales. Their structure and function can vary significantly among different species.