A thermogenic form of adipose tissue composed of BROWN ADIPOCYTES. It is found in newborns of many species including humans, and in hibernating mammals. Brown fat is richly vascularized, innervated, and densely packed with MITOCHONDRIA which can generate heat directly from the stored lipids.

Synonyms: Hibernating Gland, Tissue, Brown Adipose, Brown Fat, Brown Adipose Tissue, Adipose Tissue, Brown, Fat, Brown