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Fun Facts About Ocean Animals

Weird and wonderful true facts about sharks, octopuses, whales, seahorses and other sea creatures.

An octopus has three hearts.

Sea otters hold hands while they sleep so they don’t drift apart.

A shrimp’s heart is in its head.

Starfish have no brain and no blood.

A blue whale’s heart weighs about as much as two grown men.

One species of jellyfish can turn back into a younger form.

Greenland sharks can live for hundreds of years.

The pistol shrimp snaps its claw so fast it makes a bubble almost as hot as the Sun’s surface.

Sharks have been around longer than trees.

Sharks don’t have a single bone in their bodies.

Sharks keep growing new teeth throughout their lives.

The biggest fish in the world is a shark that eats tiny plankton.

Some sharks have to keep swimming to breathe.

Emperor penguins can dive more than 500 metres deep.

Penguins can drink seawater.

Male seahorses are the ones that get pregnant.

A mantis shrimp’s punch is fast enough to crack aquarium glass.

Dolphins sleep with half of their brain at a time.

Sea turtles return to the beach where they hatched to lay their eggs.

Tiny ocean plants make about half of the oxygen we breathe.

The Pacific Ocean is bigger than all of Earth’s land put together.

The deepest part of the ocean is deeper than Mount Everest is tall.

Shark skin is covered in tiny teeth-like scales.

Sharks have no swim bladder. An oily liver keeps them afloat.

A hammerhead’s wide head gives it a wider view and a better electric sense.

Unprovoked shark bites on people are rare: usually fewer than 100 a year worldwide.

Penguins cannot fly, but their wings work as flippers underwater.

There are more than 500 species of shark.

One of the smallest sharks is about 20 centimeters long.

Some sharks glow in the dark.

Great white sharks can grow to about 6 meters long.

Sharks have an excellent sense of smell.

Sharks can feel vibrations in the water.

Some sharks lay eggs in leathery cases called mermaid’s purses.

Sand tiger shark embryos eat their siblings before birth.

Flipping some sharks upside down makes them go still.

The shortfin mako is the fastest shark.

Bull sharks can live in fresh water.

A shark’s skeleton is made of cartilage, the same material as your nose and ears.

The extinct megalodon was one of the largest predators ever.

Each whale shark has a unique pattern of spots.

Tiger sharks are known to eat almost anything.

Many shark species are threatened with extinction.

Nurse sharks suck in their prey like a vacuum.

The goblin shark can shoot its jaws forward to grab prey.

Thousands of humpback whales visit Hawaii every winter.

Countries and states

Many penguins live mainly on krill, fish and squid.

Leopard seals are a major predator of penguins.

Florida has the only living coral barrier reef in the continental US.

Countries and states

Fun Facts About Ocean Animals: all 51, explained

An octopus has three hearts.
Two hearts pump blood through the gills, and the third pumps it around the rest of the body. The main heart actually stops beating while the octopus swims, which is one reason octopuses prefer crawling. Their blood is blue because it uses a copper-based protein, hemocyanin, to carry oxygen.
Source: Octopus (Wikipedia) · Fact card
Sea otters hold hands while they sleep so they don’t drift apart.
Sea otters rest floating on their backs, and groups called rafts sometimes link paws or wrap themselves in kelp to stay together on the current. They also have the densest fur of any animal, which keeps them warm without a layer of blubber.
Source: Sea otter (Wikipedia) · Fact card
A shrimp’s heart is in its head.
In shrimp, most of the vital organs, including the heart and stomach, sit in the front section of the body called the cephalothorax, which is the head and thorax fused together.
Source: Shrimp (Wikipedia) · Fact card
Starfish have no brain and no blood.
Sea stars use a network of nerves instead of a brain, and they move water through their bodies instead of blood. Many species can regrow lost arms, and some can regrow an entire body from a single arm with part of the central disc.
Source: Starfish (Wikipedia) · Fact card
A blue whale’s heart weighs about as much as two grown men.
The blue whale is the largest animal known to have ever lived, reaching around 30 metres long. A blue whale heart studied in Canada weighed about 180 kilograms. Its call is one of the loudest sounds made by any animal.
Source: Blue whale (Wikipedia) · Fact card
One species of jellyfish can turn back into a younger form.
Turritopsis dohrnii, the so-called immortal jellyfish, can revert from its adult form back to a juvenile polyp when stressed or injured, starting its life cycle again. It can still die from disease or being eaten.
Source: Turritopsis dohrnii (Wikipedia) · Fact card
Greenland sharks can live for hundreds of years.
A 2016 study using radiocarbon dating estimated that Greenland sharks can live at least 272 years, and possibly much longer, making them the longest-living vertebrates known.
Source: Greenland shark (Wikipedia) · Fact card
The pistol shrimp snaps its claw so fast it makes a bubble almost as hot as the Sun’s surface.
When a pistol shrimp snaps its claw, it shoots out a jet of water that forms a collapsing bubble. The collapse makes a loud crack and, for an instant, temperatures estimated at over 4,000 °C. The shock wave is enough to stun small prey.
Source: Alpheidae (Wikipedia) · Fact card
Sharks have been around longer than trees.
The earliest sharks appeared more than 400 million years ago. The first trees appeared later, around 385 million years ago. Sharks have since survived several mass extinctions.
Source: Shark (Wikipedia) · Fact card
Sharks don’t have a single bone in their bodies.
A shark’s skeleton is made of cartilage, the same flexible material in your nose and ears. Cartilage is lighter than bone, which helps sharks stay buoyant.
Source: Shark (Wikipedia) · Fact card
Sharks keep growing new teeth throughout their lives.
Sharks have rows of teeth that move forward like a conveyor belt. When a front tooth falls out, one from behind replaces it, so some sharks get through thousands of teeth in a lifetime.
Source: Shark tooth (Wikipedia) · Fact card
The biggest fish in the world is a shark that eats tiny plankton.
The whale shark can grow to about 18 metres long, but it is a gentle filter feeder. It swims with its mouth open, straining plankton and small fish from the water.
Source: Whale shark (Wikipedia) · Fact card
Sharks can sense the electric fields of other animals.
Jelly-filled pores on a shark’s snout, called ampullae of Lorenzini, detect the tiny electric signals made by the muscles and nerves of prey, even when it is hidden in sand.
Source: Ampullae of Lorenzini (Wikipedia) · Fact card
Some sharks have to keep swimming to breathe.
Species such as the great white and mako rely on "ram ventilation": swimming with their mouths open so water flows over their gills. Other sharks can pump water over their gills while resting on the sea floor.
Source: Shark (Wikipedia) · Fact card
Emperor penguins can dive more than 500 metres deep.
The emperor penguin is the deepest-diving bird. Dives of over 500 metres have been recorded, and they can stay underwater for more than 20 minutes while hunting fish, squid and krill.
Source: Emperor penguin (Wikipedia) · Fact card
Penguins can drink seawater.
A gland above a penguin’s eyes filters excess salt from its blood. The salty fluid drains out through the bill, which is why penguins sometimes seem to sneeze or drip.
Source: Supraorbital gland (Wikipedia) · Fact card
Male seahorses are the ones that get pregnant.
The female places her eggs in a pouch on the male’s belly. He fertilises and carries them until they hatch, then releases tiny baby seahorses into the water.
Source: Seahorse (Wikipedia) · Fact card
A mantis shrimp’s punch is fast enough to crack aquarium glass.
Some mantis shrimps strike with club-like limbs at speeds of around 23 metres per second. The blow is so fast it forms collapsing bubbles that deliver a second shock to the prey.
Source: Mantis shrimp (Wikipedia) · Fact card
Dolphins sleep with half of their brain at a time.
Dolphins must choose when to breathe, so they cannot fully fall asleep. They rest one side of the brain while the other stays alert, and often keep one eye open.
Source: Unihemispheric slow-wave sleep (Wikipedia) · Fact card
Sea turtles return to the beach where they hatched to lay their eggs.
Female sea turtles often travel thousands of kilometres to nest near the beach where they themselves hatched. Scientists think they use Earth’s magnetic field to find their way.
Source: Sea turtle (Wikipedia) · Fact card
Tiny ocean plants make about half of the oxygen we breathe.
Phytoplankton, microscopic plant-like organisms near the ocean surface, carry out about half of the photosynthesis on Earth.
Source: Phytoplankton (Wikipedia) · Fact card
The Pacific Ocean is bigger than all of Earth’s land put together.
The Pacific covers about 165 million square kilometres, roughly a third of Earth’s surface and more than the area of all the continents combined.
Source: Pacific Ocean (Wikipedia) · Fact card
The deepest part of the ocean is deeper than Mount Everest is tall.
The Challenger Deep in the Mariana Trench is about 10,900 metres deep. If Everest were placed at the bottom, its peak would still be more than 2 km underwater.
Source: Challenger Deep (Wikipedia) · Fact card
Shark skin is covered in tiny teeth-like scales.
Shark skin is made of dermal denticles, small scales built like teeth. They feel rough one way and smooth the other, and reduce drag as the shark swims.
Source: Fish scale (Wikipedia) · Fact card
Sharks have no swim bladder. An oily liver keeps them afloat.
Most bony fish use a gas-filled swim bladder to float. Sharks instead have a large liver full of oil, which is lighter than water.
Source: Shark (Wikipedia) · Fact card
A hammerhead’s wide head gives it a wider view and a better electric sense.
Eyes at the ends of the hammer-shaped head give hammerheads a broad field of vision, and the wide head carries more electric-sensing pores to scan the sea floor.
Source: Hammerhead shark (Wikipedia) · Fact card
Unprovoked shark bites on people are rare: usually fewer than 100 a year worldwide.
The International Shark Attack File records the cases each year. People kill tens of millions of sharks every year, mostly through fishing.
Source: Shark attack (Wikipedia) · Fact card
Penguins cannot fly, but their wings work as flippers underwater.
Gentoo penguins are the fastest swimmers, reaching about 36 km/h.
Source: Gentoo penguin (Wikipedia) · Fact card
There are more than 500 species of shark.
They range from the dwarf lanternshark, small enough to hold in your hand, to the whale shark.
Source: List of sharks (Wikipedia) · Fact card
One of the smallest sharks is about 20 centimeters long.
The dwarf lanternshark lives deep in the Caribbean and can glow in the dark.
Source: Dwarf lanternshark (Wikipedia) · Fact card
Some sharks glow in the dark.
Lanternsharks and others make their own light, which may help camouflage them from below.
Source: Lanternshark (Wikipedia) · Fact card
Great white sharks can grow to about 6 meters long.
They are the largest predatory fish, feeding on seals, fish and dolphins.
Source: Great white shark (Wikipedia) · Fact card
Sharks have an excellent sense of smell.
Some sharks can detect blood at concentrations as low as about one part per million.
Source: Shark (Wikipedia) · Fact card
Sharks can feel vibrations in the water.
A line of sensory cells along each side, the lateral line, picks up movement and pressure changes from prey.
Source: Lateral line (Wikipedia) · Fact card
Some sharks lay eggs in leathery cases called mermaid’s purses.
Others give birth to live young. Empty egg cases often wash up on beaches.
Source: Egg case (Chondrichthyes) (Wikipedia) · Fact card
Sand tiger shark embryos eat their siblings before birth.
The largest embryo in each womb eats the others, so only one pup is born from each side.
Source: Sand tiger shark (Wikipedia) · Fact card
Flipping some sharks upside down makes them go still.
This trance-like state is called tonic immobility, and researchers use it to handle sharks safely.
Source: Tonic immobility (Wikipedia) · Fact card
The shortfin mako is the fastest shark.
It can reach bursts of about 70 km/h and leap high out of the water.
Source: Shortfin mako shark (Wikipedia) · Fact card
Bull sharks can live in fresh water.
They have been found far up rivers such as the Mississippi and the Amazon.
Source: Bull shark (Wikipedia) · Fact card
A shark’s skeleton is made of cartilage, the same material as your nose and ears.
Cartilage is lighter and more flexible than bone, which helps sharks stay buoyant and turn quickly.
Source: Cartilage (Wikipedia) · Fact card
The extinct megalodon was one of the largest predators ever.
It lived until about 3.6 million years ago and may have reached 15 meters or more. We know it mostly from huge fossil teeth.
Source: Megalodon (Wikipedia) · Fact card
The cookiecutter shark bites round plugs out of bigger animals.
It latches on with its lips and twists, leaving neat circular wounds on whales, dolphins and even submarines.
Source: Cookiecutter shark (Wikipedia) · Fact card
Each whale shark has a unique pattern of spots.
Scientists identify individuals from photos of their spots, using software first designed for star maps.
Source: Whale shark (Wikipedia) · Fact card
Tiger sharks are known to eat almost anything.
Their stomachs have contained turtles, birds, tires and license plates.
Source: Tiger shark (Wikipedia) · Fact card
Many shark species are threatened with extinction.
Overfishing, including for shark fins, has cut some populations sharply, and about a third of shark and ray species are threatened.
Source: Shark finning (Wikipedia) · Fact card
Nurse sharks suck in their prey like a vacuum.
They rest on the sea floor and use powerful suction to pull fish and shellfish from crevices.
Source: Nurse shark (Wikipedia) · Fact card
The goblin shark can shoot its jaws forward to grab prey.
This rarely seen deep-sea shark has a long flat snout and slingshot jaws.
Source: Goblin shark (Wikipedia) · Fact card
Thousands of humpback whales visit Hawaii every winter.
They migrate from Alaska to the warm, shallow waters around the islands to breed and give birth.
Source: Humpback whale (Wikipedia) · Fact card
Many penguins live mainly on krill, fish and squid.
Krill, tiny shrimp-like animals, are a key food for Adélie and chinstrap penguins in the Southern Ocean.
Source: Antarctic krill (Wikipedia) · Fact card
Leopard seals are a major predator of penguins.
They often wait near the ice edge where penguins enter the water.
Source: Leopard seal (Wikipedia) · Fact card
Florida has the only living coral barrier reef in the continental US.
The Florida Reef runs along the Florida Keys.
Source: Florida Reef (Wikipedia) · Fact card

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