Joel Allen

Joel Asaph Allen (July 19, 1838 – August 29, 1921) was an American zoologist, mammalogist and ornithologist. He became the first president of the American Ornithologists' Union, the first curator of birds and mammals at the American Museum of Natural History, and the first head of that museum's Department of Ornithology. He is remembered for Allen's rule, which states that the bodies of endotherms (warm-blooded animals) vary in shape with climate, having increased surface area in hot climates to lose heat, and minimized surface area in cold climates, to conserve heat.