Some species of fish like the swordfish, tuna fish and some shark species can raise the temperature of specific organs which helps them swim faster and catch prey. But that is the closest to warm-blooded they can ever get.
However, a team of researchers from the National Oceanic and Atmospheric Administration (NOOA) has discovered that the giant Opah fish is actually the first warm-blooded species of fish. The ability of increasing the temperature of the body is called endothermy.
According to the new research, the opah fish can keep warm its entire body by maintaining a high temperature, which could be 5 degrees higher than its surroundings.
Although the opah fish cannot raise its body temperature to be as warm as that of mammals or birds, the experts say that this ability is quite unique among species of fish.
The opah is a large fish that can grow as big as car tire; it can reach up to two meters in length, with a silver body and red fins.
The opah fish is a fast swimming predator that lives in deep, dark, cold water.
Usually, fish that live in such deep waters are very lazy and catch their prey using ambush techniques, which helps them conserve the energy.
But unlike other species that live on the bottom of the sea, the opah is very agile and can heat its body by flapping its fins.
This also helps the fish speed up its metabolism, its movement and the animal’s reaction time.
Because it’s a warm-blooded creature, the opah fish is a great predator that swims faster, sees more sharply and reacts more quickly, compared to other species of fish.
Nicholas Wegner, a biologist at NOOA Fisheries’ Southwest Fisheries Science Center in La Jolla, California, explained that before this recent discovery, researchers assumed that the opah was a fish that moves slowly, like most of the fish the live in such deep and cold environments.
But because the fish has the ability of warming its own body, it turns it into a very agile, active predator that chases down fast-moving prey like squid. The opah fish can also migrate for very long distances, Wegner said.
The researchers detailed their findings about opah, the first warm-blooded fish, in the journal Science.
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