Are tunas warm-blooded?

In this article, we will answer the question “Are tuna warm-blooded?” and will discuss what attributes of tuna make it warm-blooded.

Are tunas warm-blooded?

Yes, tuna is warm-blooded.

 In reality, tuna and mackerel sharks are two of the very few warm-blooded fish. They have organs called “retia mirabilia,” which are a network of tiny veins and arteries that feed oxygenated blood to the swim muscles and drain exhausted blood. This is one of several modifications that allow them to hunt at fast speeds.

There are some of the world’s quickest fish in the tuna clan. Aside from the lunate tail and fin grooves, everything about them is built for speed (to make the tuna more aerodynamic). Even the way they move their tail is a speed adaptation, with only the very end of their body going side to side at high speed rather than the entire body moving in sinusoidal waves (like most other fish do).

Tuna must maintain a high metabolic rate to sustain that pace for long periods, which is exceedingly difficult to achieve if their body is at room temperature, as most metabolic functions are temperature dependent. Therefore, they maintain a greater body temperature than the surrounding air.

Tuna flesh’s characteristic red color is another adaptation for sustaining a high metabolic rate (and high level of activity) over long periods. Myoglobin (an oxygen-carrying molecule similar to hemoglobin in blood) is generated in the tuna’s muscle and helps deliver oxygen to the muscles to give it endurance.

Why tuna is warm-blooded

When you work as a deep-sea fisherman in Hawaii, you discover a lot of interesting fish facts. These data, among other things, assist us in determining their behavior and routines. One of the strangest fish facts you’ll ever learn.

Warm-blooded fish exist. Mammals are warm-blooded, but reptiles and fish are cold-blooded, as we learn in school. Although this is largely accurate, certain fish have acquired a form of warm-bloodedness to assist them to regulate their body temperature. Aside from tuna and sharks (particularly the Great White Shark, a fan favorite), there are no other warm-blooded fish. Warmth-bloodedness isn’t as complete in birds as it is in mammals. Blood arteries in tuna help them regulate the temperature of their organs and swimming muscles.

Tuna’s gills are the main area where they lack this characteristic. This is important because the water travels through them and exchanges a lot of heat. In reality, these blood vessels can only be found in the gills of one fish. The only fish with full-body warm-bloodedness is the opah, which can only be found in the seas around Antarctica. Deep-sea fishing in Hawaii is a lot more pleasant, believe us.

Tuna has what are known as regional warm-blooded characteristics. If they have both warm and cold blood, they’re probably a cross between the two. Because the seas of Hawaii are usually warm and soothing, tuna doesn’t have to increase their body temperature very much. Tuna’s behavior is influenced by its warm-blooded characteristics. Warming up the muscles of tuna in Hawaii might give it an additional burst of speed.

A bluefin tuna can reach speeds of 30 mph in a 10-second sprint. That’s very impressive for an animal that weighs on average 130 pounds and may grow to be over 900 pounds. That surge alters the way we catch tuna in particular ways, and science explains why: their muscles are already warmed up.

The University of Manchester, in collaboration with Stanford University in the United States, has found how coveted bluefin tuna maintain their hearts beating amid temperature fluctuations that would stop a human heart. The study contributes to the understanding of how animals react to fast temperature fluctuations, which is becoming increasingly relevant as the world heats.

 Pacific bluefin tuna are apex predators known for their epic Pacific Ocean migrations. They’re also uncommon among bony fish in that they’re warm-blooded (endothermic) and can raise their core body temperature to 20°C above the ambient temperature.

 The university’s Faculty of Life Sciences’ Dr. Holly Shiels says: “Tunas’ body temperature remains constant when they dive to frigid depths, but their heart temperature drops by 15°C in minutes. The heart is chilly because it takes blood straight from the gills, which has a temperature that is similar to that of the water.

The heart is visibly stressed as a result of this, yet it continues to beat despite the temperature drop. The heart would cease in most other mammals.” The mismatch between the heated swimming muscles of tunas and the cardiac system that functions at water temperature is a conundrum the team has been attempting to solve for a long time.

Other FAQs about Tuna that you may be interested in.

Can I feed my dog canned tuna?

How many times a week can you eat tuna?

What is the difference between albacore and yellowfin tuna?


In this brief guide, we answered the question “Are tuna warm-blooded?” and discussed what attributes of tuna make it warm-blooded.