Brown adipose tissue (BAT) is a type of fat found in the body that is primarily responsible for generating heat. Unlike white adipose tissue, which stores energy, BAT contains a high number of mitochondria and is rich in iron, giving it a brown color. This tissue is especially abundant in newborns and hibernating mammals, helping them maintain body temperature in cold environments. BAT functions by burning calories to produce heat through a process called non-shivering thermogenesis. This process is activated by cold exposure and certain hormones, such as norepinephrine. Research into BAT has gained interest due to its potential role in combating obesity and metabolic disorders by increasing energy expenditure.