What Do Sea Urchins Eat?

what do sea urchins eat

While more and more people keep sea urchins as pets at home, you might be searching what food do sea urchins eat.

Sea urchin feeds on everything that floats around it. They primarily feed on algae attached to coral and rocks, but they also grind and eat plankton, kelp, and periwinkle. They also consume dead fish, mussels, sponges, and barnacles.

Let’s learn more about sea urchin’s feeding behavior in their natural habitat.

What Do Sea Urchins Eat?

Sea urchins, sometimes known as just ‘urchins,’ are spherical, symmetrical creatures, classed as Echinoidea.

They have hard shells; called tests, surrounded with defensive spines; that stick out around them. Some sea urchins have spines toxic to other creatures and can be painful if trod on by humans.

The name urchin is actually an old English word for ‘hedgehog,’ given to it because they are both covered in similar spikes. Sea urchins are quite small, with the largest size being roughly 10 cm in diameter. Sea urchins move slowly across the ocean floor, crawling along on five rows of hundreds of small, transparent, tube-shaped feet.

Sea urchins can be found in all of the world’s oceans and have thrived for over 450 million years. Their closest living relatives are sea cucumbers.

The red sea urchin is the longest living creature on earth, with some living for over 200 years. Sea urchins can often be found in shallow, coastal areas, searching for food.

Sea urchins are omnivorous animals. Sea urchin primarily feeds on algae attached to coral and rocks, but they also grind and eat plankton, kelp, and periwinkles. Sea urchins eat decomposing materials found on the ocean floor, such as dead fish, mussels, sponges, and barnacles.

Now that we have looked at the type of food sea urchins eat, what about the way they eat? Sea urchins eat using a structure called Aristotle’s lantern, which is located on their body’s underside.

It is made up of five strong arrow-shaped plates known as pyramids, that each has a tooth at the top, and which move towards each other to form a beak-like shape.

They scrape clean rocks and coral covered in algae using their teeth and their long tongue to eat the matter. Sea urchins excrete waste matter through the top of their bodies.

Sea urchins predators

The sea urchin’s main predators are crabs, lobsters, starfish, eels, sea otters, birds, and a number of large fish. Sea urchins are also sought after by humans as a delicacy in some areas of the world.

What does a pencil sea urchin eat?

The food that pencil sea urchins eat is generally similar to its sea urchin cousins. The main difference between their feeding habits is that pencil urchins are nocturnal and tend to feed more at night.

Is the sea urchin a herbivore?

As sea urchins are known to eat dead and decomposed animal matter, they are not herbivores. They eat algae and sea plants like kelp; they are considered omnivores; creatures that eat meat and vegetation.

What is the role of a sea urchin in the ecosystem?

Sea urchins are very important to the ecosystem of coral reefs. They play a critical part in maintaining the balance between the number of algae that collects on corals.

Without sea urchin in the ocean, there would be too many algae in some areas, which can affect the entire reef’s health.

Due to human activities and climate change, some species that consume algae have been decreasing worldwide. This includes sea urchins.

To maintain reefs and other ocean environments, it is more important than ever to ensure that humans stop interfering with and upsetting the delicate balance of the ocean ecosystem.

This video shows a sea urchin eating, displaying its mouth!

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