Sharks are some of the most well-known marine animals that are found in all five of our planet’s oceans, from shallow coastal waters to the deep blue.
They are notorious predators, with some species being as large as 6.5 meters long and weighing a whopping 1,100kg.
Today we’re going to take a look at how sharks thrive in different waters and how their bodies adapt to changes in water temperatures.
We are going to answer a question that often comes up when discussing sharks and their habitats. Are sharks warm blooded?
No, most sharks are in fact cold-blooded, or ectothermic. Their body temperatures match the temperature of the water surrounding them, meaning in warm waters they are typically warm, and in cold waters they are cool.
Are Sharks Actually Warm-Blooded?
With around 126 different species of shark, almost all are cold-blooded apart from around five that have some warm-blooded or endothermic capabilities.
Being cold-blooded means that their body temperatures change with their environment. Much like how snakes and amphibians need the sun to heat their internal temperature up.
We, humans, are warm-blooded as we maintain a stable internal body temperature no matter the weather or conditions outside.
We maintain this by having a much higher metabolism and requiring to eat multiple times per day, whereas snakes for example can go days without eating.
Are Any Sharks Warm-Blooded?
Most sharks are found in warm, tropical waters and subtropical waters where water temperatures are ideal to support some of the most powerful apex predators on earth.
Sharks that inhabit colder waters of higher latitudes or great depths do not have this luxury. They typically face lots of limitations due to this.
Sleeper sharks for example inhabit some of the coldest oceans on earth and therefore need to live with a very slow metabolism to cope with the cold waters.
This means that their growth rate is limited but also their speed, and is the reason why they are one of the slowest moving animals in the ocean.
Some sharks have managed to overcome the limitations of living in colder waters without sacrificing speed, growth rate, and fragility.
They have evolved in such a way that they can elevate and maintain body temperatures above the surrounding water temperature, essentially becoming endothermic.
Below I’ve listed some of these unique sharks that can elevate their body temperatures:
- Hammerhead shark
- Longfin mako shark
- Shortfin mako shark
- Great white shark
- Salmon shark
- Common thresher
- Bigeye thresher
The most famous of these is the great white shark, which thanks to its ability to raise its body temperature can hunt in some of the coldest waters on earth.
Why Are Some Sharks Warm-Blooded?
Great white sharks are “lamnid sharks” which have a unique system called ‘counter-current heat exchange’, which keeps their body warmer than outside conditions by +/- 10-15 C°.
The generator of this extra heat comes from the long muscles which run down the length of the shark’s body, which charge a core of ‘white muscle’ ready for quick bursts of energy even in cold environments.
This allows great white sharks to be the dominant apex predators that they are, even in the coldest waters as their body temperature can always maintain greater.
It’s what’s known as “heterothermy” which is a physiological term for animals that vary between self-regulating their body temperature and allowing the surrounding environment to affect it.
This ability allows their muscles to stay warm and helps with mobility, allowing them to burst out of the water at speed to catch their prey.
So, are sharks warm-blooded? No, for the most part, sharks are cold-blooded, however, there are some species that can raise their temperatures above the temperature of their surroundings.
This is a luxury that only a very select few species have, and it helps them to hunt in waters that they otherwise could not if they were solely ectothermic.
Being able to raise their body temperature is an ability that some sharks use when they are hunting prey, as warmer muscles tend to be more powerful and have more mobility.
Some people even believe that some sharks being able to raise their body temperature allows them to live in a broader range of temperatures and therefore be more resilient to the effects of ocean warming.
Either way, it’s a remarkable ability that allows some sharks to be formidable predators in cold waters.
Thanks for taking the time to read this post and learn more about why sharks are cold-blooded and some can become endothermic and raise their temperatures.
If you have enjoyed this post, feel free to stick around to learn more about sharks and many other types of marine wildlife.
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Hi, I’m George – the founder of MarinePatch. I created this blog as marine wildlife has been my passion for many years and I’ve spent decades learning and dedicating myself to documenting all I can about the topic.