Scuba divers get to see incredible marine species that others can only see in pictures or on television. From the oldest deep sea creatures to bucket list pelagic encounters, the opportunities are endless. Not only that, but exploring the underwater world offers a chance to discover the most ancient animal species that have been around longer than we have!

Want to know which marine species has existed the longest? Here are 12 of the oldest marine species in the ocean you can still find under the surface today.

An eel-shaped frilled shark which is an example of a prehistoric marine life species still alive in the ocean today

1. Frilled shark

With strange eel-like features, this animal doesn’t look like many of the other sharks we’re familiar with today. It is a shark though; it’s just 150 million years old and hasn’t evolved much. Of all the prehistoric creatures that still exist, the frilled shark might be one of the weirdest marine species ever!

2. Tadpole shrimp

These tiny crustaceans have been around for more than 200 million years. The survival of these ancient ocean creatures may have to do with the fact that their eggs only hatch when the environmental conditions are favorable.

A coelacanth fish which is extremely rare to see by scuba divers and one of many ancient marine species that are endangered

3. Coelacanth

Once thought to have gone extinct around the same time as dinosaurs, the coelacanths were rediscovered in 1938 off the coast of South Africa. Now over 360 million years old, these giant, prehistoric marine animals are still considered endangered and are rarely seen.

4. Sturgeon

The sturgeon is actually a family of fish that includes 27 species. They are about 200 million years old and also have a long lifespan. Some live to be 100 years old! However, overfishing and the illegal caviar trade means this oldest fish species is also one of the most endangered.

5. Horseshoe shrimp

The horseshoe shrimp is a great example of a “living fossil” – one of the oldest species on Earth that still exists today. Even after 200 million years, it seems this creature’s appearance hasn’t changed a bit. In fact, this primitive crustacean lacks eyes and is barely the size of a sesame seed!

A deep-sea Greenland shark which can live over 500 years and evolved from sharks, one of the oldest animal species on earth

6. Greenland shark

Sharks are one of the most popular marine species today, but did you know the earliest fossils date around 450 million years? Even more impressive is the elusive, deep-sea Greenland shark, which is one of the oldest living species. It’s believed they can reach over 500 years old!

7. Lamprey

The creepy-looking lamprey looks like something straight from a horror movie. It’s shaped like an eel, but these 450-million-year-old animals are actually parasites. They’re bloodsuckers that use their disc-shaped suction mouths to latch onto other marine species.

A nautilus swimming in the ocean, one of the oldest prehistoric sea creatures still alive today and now at risk of extinction
Photo credit: Klaus Stiefel

8. Nautilus

The nautilus has survived through 500 million years. Unfortunately, despite being one of the oldest animal species, it is now in danger of becoming extinct. The nautilus’s unusual and unique shell makes them a prime target for shell collectors.

9. Horseshoe crab

Just like the horseshoe shrimp, the horseshoe crab has remained unchanged throughout its existence – which has been a long 450 million years. They’re actually more closely related to spiders and scorpions than crabs, and, like their relatives, they even glow under UV light!

10. Sponges

No one’s exactly sure how old the sponge is, but scientists do know that one species dates back at least 890 million years. That’s old enough to make them one of the oldest living species on Earth still around today!

Orange jellyfish with trailing tentacles swim in blackwater which are one of the oldest sea creature species in the ocean

11. Jellyfish

Slightly over 500 million years old, jellyfish are one of the few marine species affected by climate change in a positive way. Jellyfish populations have actually increased in warmer waters. Who knows, maybe they’ll live another 500 million years!

12. Baleen whales

This toothless family of whales includes humpback, blue, and bowhead. A recent discovery of a 36-million-year-old fossil uncovered even more of these ancient animals’ history. They are relative newcomers compared to others on the list, but still one of the oldest marine mammals.

Protect the ocean’s oldest marine species

These fascinating marine species have been on the planet for millions of years, but sadly many of them are now at risk of extinction. Factors such as overfishing, illegal trade, and habitat loss mean we could lose these ancient creatures forever. On your next scuba dive, make it your mission to find – and protect – one of these 12 amazing animals!

Haven’t got a scuba certification yet? PADI is a passionate community of underwater enthusiasts motivated to protect what is worth saving – including the oldest species of marine life on the planet, from nautilus to sharks. Learning to dive will give you the tools you need to help protect the ocean and experience nature unfiltered.

Change Your Life. Create Ocean Change. Live Unfiltered.

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