American Oceans

Prehistoric Deep Sea Creatures That Are Still Alive Today

When we think of prehistoric creatures, we think of fossils and museums and documentaries attempting to explain the lives of these animals from way back in the day.

ancient coelacanth prehistoric deep sea creatures alive underwater

However, there are still a handful of creatures that have preserved throughout time, not evolving like everything else around them.

7 Prehistoric Sea Creatures

In this article, we’ll be exploring seven deep-sea creatures that have not changed a bit since before humans developed societies.


Starting with the most common-sighted creature, jellyfish are another creature that has been around for millions of years – another 500 million, to be exact.

common-sighted jellyfish creature in oceans

While they may lack blood, a heart, and a brain, and are 95% water, these critters are still technically critters!

And by that we mean, not plants. They are literally just a bunch of neurons in a slippery cover.

Additionally, while some of the creatures on this list are at risk of going extinct after surviving for so long, jellyfish are not one of them.

prehistoric jellyfish creatures population in the ocean

They thrive in oceans that are not supposed to contain life because they are too simple to be bothered by, say, a lack of oxygen and increasing temperatures.

In fact, as their predators decrease as a result of climate change, the jellyfish population is expected to boom – someday, these prehistoric creatures may rule the ocean as they did so long ago.

Horseshoe Crab

On the other end of the hard-soft spectrum, the horseshoe crab has not aged a day since prehistoric times!

horseshoe crab creatures facing extinction on beach

The horseshoe crab has not only outlived dinosaurs but has also survived five mass extinctions. Talk about perseverance!

If you go to the beach, you may see hundreds of these funny-looking critters chilling on the beach. To them, not much has changed in the past 450 million years.

Unfortunately, horseshoe crabs are facing extinction for the first time in their existence. Scientists believe that this is a result of climate change, habitat loss, and human harvesting.

So the next time you stumble upon a horseshoe crab, remember that they have literally been around since before the dinosaurs…and maybe give them some space!


Beating out the horseshoe crab on the timeline, this second hard-shelled mollusk has been around for the last 500 million years – before Pangea was even fully formed!

prehistoric hard-shelled nautilus creatures in the oceans

Nautilus’ are also at risk of extinction due to being very beautiful to humans and very slow at reproducing and growing.

Their shells come in a variety of lovely colors and patterns that are attractive to people.

Saying this, there used to be thousands of species of Nautilus. In today’s oceans, there are only a handful left.


Coelacanth are a fish that scientists ruled to have gone extinct with the dinosaurs around 65 million years ago… only for it to be rediscovered in 1938!

prehistoric coelacanth creatures with special jaw hinge

That means that these enormous fish have been around for 360 million years. Saying this, these fish seemed to have hit a pause in their evolution, as seen by a few unique anatomical features.

First, the fish has four fins that move more like limbs than fins – apparently, the coelacanth decided to rethink becoming a land-dwelling amphibian partway through the process.

The fish also has a special jaw hinge that allows it to open its mouth unnaturally large, and has a “rostral organ” that helps them detect prey: these features are no longer found in vertebrates.

Like many of the other creatures on this list, climate change is likely to wipe them out for good after a 360 million year old run (or, swim!).

Frilled Shark

The frilled shark is a funny-looking critter, but obviously, it’s doing something right because they’ve occupied the oceans for 80 million years!

prehistoric frilled shark creatures image showing throat
Credit: OpenCage

Looking more like a snake than a shark, frilled sharks are still cousins of some “actual” sharks, including the great white and the hammerhead.

They were given the name “frilled shark” because their gills have a very frilly appearance.

Also similar to a snake, these sharks have a hinged jaw and can eat pretty big creatures whole. While they sound intriguing, they don’t tend to show themselves to people.


Another ancient fish with a snake-like body, the Lamprey has survived four major extinctions in their 360 million year existence.

prehistoric lamprey creatures tongue and cartilage

They are made completely of cartilage – no bones – similar to eels, and feed by sucking the blood of other creatures like leeches.

Fun combination, no? To make matters even more fun, it’s the tongue of the Lamprey that does the damage and punctures its victim.

If you want to find this creature, they live in the Atlantic Oceans and the Great Lakes. And despite sounding terrifying.

They were once a fond meal of English kings years ago, and are being studied by scientists to help improve how we heal spinal cord injuries.

Pygmy Right Whale

Wrapping up our list today, we are going to leave off with the Pygmy Right Whale, which has been around for (just) 23 million years.

prehistoric pygmy right whale creatures sketch

It is almost never seen and is considered one of the rarest species of whale. Scientists are very unsure about a lot regarding this whale – what it eats, its behavior, and its reproduction habits.

In fact, they don’t even know where exactly the whale evolved from, which is something scientists have argued for a while.

What we do know is that they are pretty small whales that like cool waters. Because of this latter fact, scientists are worried that climate change will wipe this whale out for good.


There may not be many creatures leftover from prehistoric times, but there are a few!

The animals on this list have seen and lived through mass extinctions, the dinosaurs, and Pangea while remaining relatively the same.

So the next time you see one of them, make sure you give them a bit of respect. After all, climate change could very well destroy these ancient species for good – except the jellyfish, of course

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