Emperor penguins ’cold coat’ helps keep them warm in Antarctic winters

Emperor penguins benefit from an unusual phenomenon to stay warm during Antarctic winters, scientists at the University of Glasgow have discovered. Despite living in one of the coldest places on Earth where temperatures can reach -40 degrees Celsius, Emperor penguins retain their body heat not only because of their think plumage and layers of fat but - paradoxically - because the surface of their feathers are colder than the surrounding air. Using thermal imaging technology on penguins in Adélie Land, scientists from Glasgow's Institute of Biodiversity, Animal Health & Comparative Medicine and the Université de Strasbourg, were able to determine that the surface temperature of the birds was four degrees cooler than the surrounding air. The only parts of the penguins warmer than the air were the eyes, beaks and feet - and only the eyes were warmer than freezing. Penguins maintain a core temperature of around 36.9 degrees Celsius when incubating their young and, like any animal, will lose heat to the surrounding air as a result of thermal radiation, when heat from their warm bodies transfers to the colder air. However, because the plumage is colder than the surrounding air, computer simulations showed this 'cold coat' may gain them back a little heat from the warmer air circulating around them. Though this regained heat is unlikely to reach their skin, it could help reduce some of the heat loss from the body by thermal radiation.