Warm-blooded fish found in deep ocean
DOI: 10.1063/PT.5.028881
Los Angeles Times : Although most fish are cold-blooded, one deep-ocean dweller has been found to be completely warm-blooded. Despite the coldness of the water where it lives, hundreds of meters beneath the ocean surface, the opah manages to keep its internal body temperature 5 °C warmer than its surroundings. Through the use of sensors mounted on the fish, researchers found that nets of blood vessels located near the fish’s gills operate as a heat exchanger; they use warm blood flowing to the gills to heat up the cold blood that has just passed through. The opah generates heat constantly by the almost nonstop flapping of its pectoral fins as it swims around. Because it preys on fast-moving animals such as squid, being warm-blooded helps the opah to see better and respond more quickly.
