Scientists detailed in a new study the discovery of the first warm-blooded fish on record, a large, round fish named Lampris guttatus, or opah.
According to Live Science, opah can dive as deep as 1,300 feet below the ocean's surface and stays warm with its own endotherm system. All other known fish have exotherm systems, meaning they do not generate heat for themselves.
The new study is published in the journal Science.
"Before this discovery I was under the impression this was a slow-moving fish, like most other fish in cold environments," study lead author Nicholas Wegner, of the National Oceanic and Atmospheric Administration (NOAA) Fisheries' Southwest Fisheries Science Center, said in a press release. "But because it can warm its body, it turns out to be a very active predator that chases down agile prey like squid and can migrate long distances."
Opah manages to keep its blood warm with a "counter-current heat exchange" process akin to a car radiator. The blood pumping from the fish's core warms up the blood returning from flowing through exterior gills.
"Increased temperature speeds up physiological processes within the body," Wegner told Live Science. "As a result, the muscles can contract faster, the temporal resolution of the eye is increased, and neurological transmissions are sped up. This results in faster swimming speeds, better vision and faster response times."
Opah can grow up to six feet long and is astoundingly round for its size, but also has small fins compared to its body.
"Nature has a way of surprising us with clever strategies where you least expect them," Wegner said in the release. "It's hard to stay warm when you're surrounded by cold water but the opah has figured it out."
