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How Does The Marine Iguana Regulate Its Body Temperature

Do you want to learn more about the iguana, specifically the marine iguana?

Are you curious about how these animals can function in the variety of temperatures they do?

Marine iguanas are fascinating creatures. They’re one of the few ocean-going reptiles out there, and the marine iguanas are endangered.

As you learn about these interesting lizards, you may wonder:

How does the marine iguana regulate its body temperature?

Marine iguanas must take care to regulate their body temperatures as they dive into cold ocean waters for food. They do by basking and raising their body temperature to above its normal function. Their black scales and naturally hot island weather helps a lot with this.

Check out the rest of the article for more details.

how does the marine iguana regulate its body temperature

What Is The Normal Marine Iguana Body Temperature?

Marine Iguanas have unique body regulation needs compared to other iguanas.

As a cold-blooded creature, it’s body temperature fluctuates greatly along with the weather.

This is standard for all iguanas, which makes it difficult to label a single temperature as “normal” body temperature.

However, the marine iguana fluctuates even more than the other iguanas.

As such, it works harder to regulate its body temperature.

The goal the marine iguana always aims for is 96.8° degrees Fahrenheit (36° C).

It won’t eat if its body temperature is lower than this.

At lower temperatures, its body turns sluggish, and its heartbeat and metabolism slow down greatly.

This is normal with all cold-blooded creatures.

But the marine iguana needs to swim in the much cooler waters of the ocean to get its food. 

Learn more about what the marine iguanas eat.

During these swims, the body temperature may drop down to 50° degrees Fahrenheit (10° C).

This is much too low for many iguanas, but the marine iguana can handle this if it’s able to raise the temperature back up quickly.

This leads us to the next section.

Ways The Marine Iguana Regulates Its Body Temperature

Due to the drastic changes in the marine iguana’s body temperature when swimming in the ocean, the reptile needs special ways to get its body back up to where it needs to be.

There are a few ways the marine iguana has evolved to take care of this need as quickly as possible.

All of these ways come down to basking.

As with all reptiles, basking is key to body regulation.

Basking is simple; it’s when the animal rests directly in the sunlight where it’s warm to heat up.

On the Galápagos Islands where the marine iguana comes from, the temperature stays up, and it’s sunny much of the time.

This makes basking effective at raising body temperatures.

The marine iguana has also evolved to be black.

As you may notice, when you wear a black t-shirt on a hot, sunny day, the color black absorbs more light and heat than other colors.

This makes the marine iguana absorb heat even faster than another reptile in the same conditions.

Before diving into the ocean for food, the marine iguana will bask in the sunlight until its body gets up to a high temperature of 96.8° degrees Fahrenheit (36° C).

Then, it’ll dive in the water where it can stay underwater, searching for food for up to 30 minutes.

After it finds food, it’ll come up and back again until it reaches the previous temperature.

Once there, then it will eat the food it found. 

Marine iguanas bask in sunny spots with few shadows nearby.

They also prefer to bask on hot rocks or soil over branches, but this also isn’t uncommon.

The marine iguana’s body is thicker than many other iguana species.

This increase in muscle is better for the swimming it needs to do, but it also helps the iguana retain body heat more when in the water.

Why Are Marine Iguanas Important?

All animal species are important, and the marine iguana needs extra protection.

It’s endemic and isn’t able to be transferred to other environments easily.

It’s losing it’s land and natural food sources from settling on the islands where it lives and global warming.

Along with the people come predatory animals such as dogs, cats, and pigs.

These animals hunt down the iguana who have no natural protective instincts against such hunting animals.

As such, the numbers are in danger of dwindling to the point of extinction.

The marine iguana is a rare subspecies of the iguana genus and important to the preservation of the species.

Why Are Marine Iguanas Black?

As mentioned above, marine iguanas are black due to a forced evolutionary need.

The marine iguana has a higher need to get its body temperature up quickly after swimming.

Over the centuries, the iguanas on the Galápagos Islands evolved to be black.

The black color absorbs more light and heat, making the iguana warm up faster.

This is similar reasoning behind why most iguanas are green.

Over the centuries, the green colors allow them to better hide from predators.

Are All Marine Iguanas Black?

All marine iguanas are black when they’re young.

As they age, the colors may change slightly.

As with most iguanas, they’re capable of changing colors to a certain degree, most often when stressed or when in the breeding season.

The common color for marine iguanas as adults is still black, but there are also dark shades of red, green, and gray.

The differences in colors are largely due to the different island environments of each marine iguana.

Those without as much of a heating need won’t be as dark.


Now you know a little more about how the marine iguana regulates its body temperature.

The black-colored skin, coupled with spending a lot of time basking, helps them keep their body temperature up before they dive into the cold ocean water.

Doing the same thing after diving gets the temperature back up quickly, so they can eat their food.

Hopefully, you enjoyed learning a little more about this interesting creature.

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