The Shocking Reason Octopuses Hate to Swim

When we think of creatures with extraordinary powers, we might picture superheroes or mythical beasts. But perhaps the real champions of bizarre biology live deep beneath the ocean’s surface—like the humble, squishy, and wildly fascinating octopus.

Did you know that octopuses have three hearts? Yes, you read that right—three. Not two like the lyrics to a country love song and definitely not just one like us land-dwelling humans. These incredible cephalopods are equipped with a trio of hearts that serve different but equally important roles in keeping them alive in the often unforgiving depths of the sea.

Let’s break it down:
Two of the octopus’s hearts—called branchial hearts—are located near the gills. Their job? To pump blood through the gills, where it picks up oxygen. Once the blood is oxygenated, it’s the third heart’s time to shine. Known as the systemic heart, this one pumps the oxygen-rich blood through the rest of the body, supplying energy to the arms, brain, and all the weird, wonderful parts in between.

But here’s where things get really interesting.

When an octopus swims, its main heart—the systemic one—actually stops beating.
That’s right. The very mechanism designed to deliver oxygen and energy throughout its body pauses when the octopus is in motion. This means swimming isn’t exactly effortless for our eight-armed friends. In fact, it’s downright exhausting.

Unlike fish, which glide through water with relative ease, octopuses rely on jet propulsion to get around—pulling water into their mantle cavity and forcefully expelling it through a siphon. It’s fast, and when they’re evading predators, it’s effective. But it’s also energy-intensive. So much so, that they can only swim in short bursts before they need to rest.

That’s why, most of the time, octopuses prefer to crawl. They’ll use their flexible, sucker-lined arms to shuffle along the seafloor or wedge themselves between rocks, quietly observing, hiding, or hunting. It’s a slower, more energy-efficient lifestyle—perfect for a creature whose heart literally takes a break when it tries to sprint.

But the heart situation isn’t the only thing that sets the octopus apart.

Their blood is another oddity. It’s blue, not red. Why? Because it contains hemocyanin, a copper-based molecule that transports oxygen, instead of the iron-based hemoglobin found in our blood. Hemocyanin works better in cold, low-oxygen environments, which makes it ideal for the deep-sea habitats many octopuses call home.

And just when you thought they couldn’t get weirder—or cooler—consider this: octopuses are also insanely intelligent. Studies have shown they can solve puzzles, recognize human faces, use tools, and even play. They’ve been observed unscrewing jar lids, escaping from aquariums, and rearranging furniture in their tanks. With brains distributed throughout their arms (each arm can operate semi-independently), and a central brain that’s relatively large for an invertebrate, these creatures are some of the smartest animals in the ocean.

So what do we take away from all this?

Sometimes, the most incredible feats of nature aren’t the loudest or flashiest. They’re quietly crawling across the ocean floor with a blue-blooded cardiovascular system that defies logic and a brain that puts some mammals to shame. The octopus may not have the grandeur of a lion or the wingspan of an eagle, but in terms of adaptability, mystery, and biological oddity, it reigns supreme.

This Saturday, share that fun fact at brunch or during your weekend trivia night:
“Did you know octopuses have three hearts and their main heart stops beating when they swim?” It’s the kind of fact that makes people pause, smile, and wonder what else is out there that we’ve yet to discover.

Because in the end, learning something new—especially about the world around us—is always a win. And just like the octopus, we’re all just doing our best to keep moving forward… even if our hearts need a break sometimes.