Three most intelligent sea creatures

Ian Carroll

It’s hard to tell what makes an animal intelligent. As the self-proclaimed most intelligent species on the planet, humans have been searching for the answer for a long time. Although we are a lot closer than in decades past, there still isn’t a clear answer.

Is it the size of an animal’s brain that makes it intelligent? Is it an animal’s problem solving and capacity to learn? Or could it be a deeper emotional intelligence that indicates higher orders of thinking? We don’t have answers to those questions, and it’s possible we never will.

However, there are some creatures on the land and in the sea that are clearly smarter than their contemporaries. It’s obvious to most of us that creatures like crabs and anemones probably aren’t reading at a college level. Or that sharks are probably driven by more primal instincts than by intelligent thought.

So, here’s a list of the most intelligent sea creatures we know of today. Some of them have been on this list for years. Others have long been labeled as less than spectacular. However, new scientific understandings are emerging in all fields. The study of marine animals is no exception. Who knows, maybe next year we’ll discover an entirely new species in the deepest depths of the ocean that are even smarter than us? I hope not though…

Manta Rays

Manta rays can grow to be pretty big.
Manta rays can grow to be pretty big.

For a long time, no one thought much of these bizarre ocean giants. However, recent research is showing that they may be alongside dolphins at the top of the class, so to speak. Manta rays have huge brains. Their brains are bigger than any fish and have vast areas associated with learning, problem-solving, and communication. A manta ray’s brain can be up to ten times larger than that of a whale shark. Which is staggering considering that whale sharks are the largest known fish in the sea. A manta’s brain is also large relative to the ray’s body. This is a classic indicator of advanced intelligence. We see this in other species like humans, dolphins, and elephants.

In their spare time, mantas like to fly. Usually, at dawn and dusk, entire schools can be seen jumping together, much like dolphins. In the ocean, mantas actually show curiosity about divers and will intentionally come to interact and play. There are no other species of fish that demonstrates this behavior. Furthermore, recent studies have shown that mantas likely are capable of recognizing their own reflection. Very few species on the planet have this ability. Among them are some species of great apes and bottlenose dolphins.

Cetaceans (dolphins, whales, and porpoises)

One of the most revered and well-respected creatures in the sea are dolphins. We’ve known for a long time of their exceptional intelligence. Dolphins, or rather, all cetaceans have the ability to convey up to 20 times the amount of auditory information as humans can. That may be because cetacean’s primary sense and primary mode of communication are the same – auditory. Humans, on the other hand, use vision primarily but communicate vocally.


When most people think of smart marine mammals, they immediately think of dolphins. And it’s true, dolphins have been shown to be some of the smartest animals in the sea. Not to mention the entire planet. There are even some scientists that argue they may have more advanced brains than humans. After all, just because they don’t build cities and spaceships doesn’t necessarily mean they don’t know as much or more than us.

As previously mentioned, bottlenose dolphins are among the only animals on the planet that have been shown to recognize themselves in mirrors. Furthermore, dolphins have been recorded on many occasions to rescue people and dogs stranded at sea by swimming them to shore. They like to play and have deep emotional connections to their pod.

However, the Cetacean order includes far more than just dolphins. Whales and porpoises are also included. That means everything from the blue, sperm, and humpback whales, to the orca, porpoise, and narwhal. All of these creatures have evolved from common ancestors. All of them have the same advanced auditory structures and capacity for intelligence. Dolphins just seem to be the top achievers. Some researchers speculate that it’s because they live in large pods and are more social than other cetaceans.

Cephalopods (octopuses, squids, and cuttlefish)

If you’re scared of giant squids and deep-sea monsters, things are about to get pretty scary. That’s because cephalopods are well known to be the most intelligent invertebrates on the planet. Most of this intelligence is thought to be linked to predation. Many of their intelligent traits can be linked to hunting behaviors and self-defense.

Octopus in the wild
Octopus in the wild

All cephalopods are carnivorous predators. Many types of squid hunt in packs (schools?) and apply devastatingly intelligent tactics. Octopuses have been shown to steal bait from lobster traps to use it in setting their own. Octopuses in aquariums and labs have also been recorded escaping their own tanks, entering nearby ones to eat fish and then sneaking back into their own tanks before anyone realized. Hooded Octopi have even been observed severing the poisonous tentacle of a Portuguese man of war and wielding it like a sword in self-defense.

They can use tools and understand complex problem-solving. One octopus in Germany named Otto learned he could escape his tank and then squirt water at an overhead light causing the entire lab to lose power. He was recorded to have done this multiple times. Keeping octopuses in tanks is not an easy undertaking. Especially considering that they can squeeze their whole bodies through tiny openings (think the width of the last paperback novel you read.) Keeping octopuses in jars isn’t any easier, because they can unscrew them from the inside.

That brings us to one of the most fascinating things about cephalopods. Their brains are not at all like those of vertebrates and all of the other intelligent sea creatures on this list. Instead, their brains are distributed throughout their bodies. In some ways, each of their eight tentacles actually has a mind of its own. Although we have only a very limited understanding of just how smart cephalopods are, one thing is clear. It’s a good thing that they’re small… oh, wait… giant squids.

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ian-carroll is one of the authors writing for Outdoor Revival