If Godzilla existed in real life, he wouldn't be able to stand up

• Since his debut in 1954, Godzilla has gotten bigger and bigger.
• In 2019's "Godzilla: King of the Monsters", he's bigger than ever, towering at a whopping 119 meters. At that size, his heart wouldn't be able to pump blood to his brain.
• His brain would send messages too slowly to his muscles, so he wouldn't be able to move properly either.
• Plus, he'd either have to spend all his time sunbathing to stay warm, or produce his own body heat and cook himself.
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The newest Godzilla is bigger than ever, towering at a whopping 119 meters. At that size, his heart wouldn't be able to pump blood to his brain. And if he were a reptile, he'd have to spend all his time sunbathing to keep warm, while a mammal of his size would cook itself with its own body heat.

Following is a transcript of the video.

Narrator: The roar belongs to one of the most iconic movie monsters of all time: Godzilla. Since his debut in 1954, the King of Monsters has rampaged across Tokyo, New York City, and Osaka to name a few. And over the years, he's gotten bigger, and bigger, and bigger. The latest Godzilla is a record 119 meters tall, about six times taller than the tallest animal in history. And to be fair, it's a fantasy film, not a nature documentary.

But just how fantastical is a 36-story-tall lizard-dinosaur creature who breathes beams of atomic energy? Well, energy beams aside, Godzilla is actually even more unrealistic than you might think. Now, Earth is no stranger to enormous animals.

Just look at the largest dinosaur, the titanosaurs, or today's blue whales, which reach up to 30 meters long and can weigh 200 tons. Compared to them, Godzilla doesn't seem that impossible, right?

Mike Habib: These critters are massive on a scale that's just totally impossible. I mean, assuming, at least, they're made of anything even remotely like what we're made out of and follow any of the roles of biology, they are completely impossible.

Narrator: That's paleontologist Mike Habib. He's an expert in giant reptiles and also helps design fantastical creatures for TV and film. And according to him, a creature like Godzilla could never exist in real life for multiple reasons. First, he would be brain-dead long before he ever reached a city because his heart simply isn't large and powerful enough to pump blood to his head.

Mike Habib: His heart would have to be thousands of tons and fill most of his chest. You'd have to have vessels that you could drive a car through, and he would need the energy consumption of a small power plant, probably, every minute in order to run it. Of course, he's nuclear-powered, so maybe he has the energy to spare.

Narrator: In reality, large animals like titanosaurs got around this by walking on all fours with their heads held out in front them, not held up high. That way, they don't have to pump blood against gravity as far. But even if Godzilla did crawl across cities on all fours, he'd have another problem: movement.

You see, whenever you lift your leg or arm, it's because your brain fires signals to the nerves in your leg and arm muscles. The fastest of these signals travel around 100 meters per second, so the message from brain to leg is virtually instantaneous. Not for Godzilla though. It would take more than a full second for nerve signals to travel the length of his body. Now, a second still sounds pretty quick, but in reality...

Mike Habib: His nerve-conduction speed becomes so slow that he can't move. Takes forever to do anything.

Narrator: Now, Godzilla does look pretty sluggish in the films, but it turns out, in reality, it would look more like this. But even if Godzilla could move super fast, he wouldn't have time to fight enemies or demolish buildings because he'd be too busy sunbathing. All animals need a way to regulate body temperature. Reptiles and other cold-blooded animals stay warm by basking in the sun.

But in Godzilla's case, heat from the sun would have to travel through meters upon meters of tissue to penetrate his hide and reach his internal organs. So to stay warm, he'd have to spend hundreds of hours straight sunbathing. But what if Godzilla were more like a mammal? Like us? He wouldn't need to rely on the sun since we warm-blooded creatures produce our own body heat. But unfortunately, that would cause yet another problem.

Mike Habib: But then he's so big, he probably cooks himself. His core temperature hits 300 degrees.

Narrator: Yikes. And even if he somehow got around all these problems, his skeleton would still collapse under its own weight. Now, Mike says he's a whopping 90,000 metric tons, and that skeleton's just not strong enough to support 90,000 metric tons of, well, anything.

Mike Habib: Yeah, he would just crumple. Yeah. He'd just collapse. He'd be a very large pile of meat.

Narrator: Not a very intimidating picture. In the end, Mike says Godzilla could only be about half as tall as he was in the original film before his poor heart would give out. But just because Godzilla's body is unrealistic doesn't mean it's bad. In fact, he's perfect for the role. He's tall enough to stalk past city skyscrapers, which give us iconic scenes like this.