Fun Barnacle Facts For Kids

Moumita Dutta
May 10, 2023 By Moumita Dutta
Originally Published on Aug 05, 2021
Edited by Monisha Kochhar
Barnacle facts help to know more about animals.
Age: 3-18
Read time: 6.3 Min

Are you ready to read about one of the most interesting crustaceans that live on our planet? Then let us learn a bit more about the Barnacles. These funny named animals are found globally in the intertidal zone and beside marine water. The Barnacles attach themselves to hard surfaces either with the help of their shells or with their stalk. The tough shells of these crustaceans protect their delicate body. They have a look that may make them similar to a snail, but they are closer to crabs. Barnacles may also live in shallow water or piggyback on other water animals like whales and sea turtles for their whole lifespan to gather food. It is hard for predators to evade the shell of Barnacles, but they still have some threats from predators like whelks, mussels, starfish, and the good old humans. You can try spotting them near water, but be aware of trampling on them as the thick and sharp shell may cut your foot. Keep reading to know more about the Barnacles.

Find the Barnacle facts interesting? Check out seahorse and sea snake facts to know more about the ocean.

Barnacle Interesting Facts

What type of animal is a Barnacle?

Barnacles are arthropods that are closely related to crabs and lobsters.

What class of animal does a Barnacle belong to?

Barnacles are part of the class Maxillopoda, the subclass Thecostraca, and the infraclass Cirripedia.

How many Barnacles are there in the world?

More than 1,320 species of Barnacles are found around the world, and they reproduce prolifically. Hence, it is almost impossible to find out the exact number of Barnacles that live in this world.

Where does a Barnacle live?

Barnacles are usually found in marine habitats. Acorn Barnacles cement themselves to hard surfaces beside the ocean or in shallow waters and intertidal zone. However, many adult Barnacles live inside the sea, or they may even cement themselves to other animals like whales and turtles.

What is a Barnacle's habitat?

Barnacle dwells in marine habitats. Species of Barnacles like the Acorn Barnacle attach themselves to rocks or boats. One of the exceptions is the Rhizocephala barnacles that are predators to crustaceans. However, as Barnacles are stationary, they can also attach to animals like whales and sea turtles while feeding on planktons and algae while the host travels through the ocean.

Who do Barnacles live with?

Barnacles are often found in clusters where most of the clutch of hatched larvae will cement themselves to a hard surface after reaching the adult stage. Clusters of Barnacles are also found living on animals like whales, sea turtles, or crabs.

How long does a Barnacle live?

The lifespan of a Barnacle depends on its species. They can live for as low as 18 months, while some Barnacles have lived a long life of 10 years or more. The average lifespan for Acorn Barnacles is 5-10 years.

How do they reproduce?

Well, here are the interesting facts about these crustaceans. Most Barnacles are considered hermaphroditic (they contain both male and female sexual characteristics). However, it is seen that an Acorn Barnacle lacks the ability to self-fertilize themselves. This is one of the unique Acorn Barnacle facts. So, the Barnacles have to mate with others surrounding them to increase their population. Interestingly, some Barnacles also reproduce via sperm casting, where the males of the species shoot their sperm into the water, which is caught by the females for reproduction.

Barnacle eggs hatch inside their body, and they expel hundreds of larvae. Barnacle species have two distinct larval stages, the Nauplius larval stage, and the Cyprid larval stage. In the Cyprid stage, the larvae float in the water to make their final journey of cementing themselves to a permanent surface. The larvae use antennules as a way to sense a good place and then attach themselves to the surface. The growth of a Barnacle to a full-blown adult starts after the larvae finds a suitable surface. Adult Barnacles have hard calcareous shells protecting them. For instance, the Acorn Barnacle has six hard plates.

What is their conservation status?

No particular conservation status has been assigned to the numerous species of Barnacles.

Barnacle Fun Facts

What do Barnacles look like?

People who have trypophobia (a fear or aversion towards small holes) should be warned about looking at these species. Barnacles belong to the Cirripedia infraclass, so they have hard plates or shells protecting their fragile body, which also makes them related to crabs. Most of them have a round calcareous shell covering on them which may appear pointy. The color of a Barnacle may differ according to its species. Usually, it is found in colors like white, gray, yellow, pink, green, and brown. It is also usual to see their plates being covered with green substances from algae or other plants. Goose barnacles are a Cirripedia that have a mushroom-like appearance. Barnacles are mostly found in clusters on hard surfaces.

Barnacle on beach

How cute are they?

Well, the shells and plates of the Barnacles make them have a rock-like appearance, so they aren't really cute compared to other animals.

How do they communicate?

Not much is known about the communication process of Barnacles. However, their limbs are sensitive, so they may communicate with the help of touch. Other than that, Barnacles also have multiple photoreceptors for judging day from night.

How big is a Barnacle?

The average size of a Barnacle is of the length 0.5-1 in (1.2-2.5 cm) and height 0.5-1.5 in (1.2-4 cm). However, the species Balanus nubilus is the world's largest Barnacle with a length of 6 in (15 cm) and a height of 12 in (30 cm). Barnacles are similar to the size of the Marsh Fiddler Crabs that are also able to grow to a length of about 1 in (2.5 cm).

How fast can Barnacles move?

Barnacles lack the ability to move once they have reached adulthood.

How much does a Barnacle weigh?

Not much is known about the individual weight of a Barnacle, and a lot of it will depend on the shell size.

What are their male and female names of the species?

There is no distinct name for the male and female of the Barnacle species as most of them are hermaphroditic in nature.

What would you call a baby Barnacle?

A baby Barnacle is called a larva (plural larvae).

What do they eat?

Barnacles feed themselves on plankton and algae that they hunt with their legs which have a special organ called Cirri that helps them to gather nutrition. They may also depend on detritus. Some species are parasitic that live on other crustaceans. Barnacles have also been called 'filter feeders' because of their unique appendages that come out of the shell.

Are they harmful?

No, Barnacles aren't harmful except the Rhizocephala barnacles.

Would they make a good pet?

A Barnacle won't be a good pet as they need to live close to the marine water. Giving these filter feeders a good habitat in a human home is next to impossible.

Did you know...

One of the interesting Gooseneck Barnacle facts is that they have become a delicacy of seafood.

One of the fun Goose Barnacle facts is that they were thought to be actual Goose eggs during the Middle Ages.

Balanus nubilus is the world's largest Barnacle, with a length of 6 in (15 cm) and with a height of up to 12 in (30 cm).

Unusual features of the Barnacle

Barnacles lack a true heart. An esophageal sinus takes the job of the heart to pump blood. Also, Barnacles do not have gills; they take in oxygen through their limbs. And they excrete from their heads.

Different types of Barnacles

There are more than 1,320 types of Barnacles found all over the world. Acorn Barnacles and Goose Barnacles are some of the species seen all over the world. Barnacles are mainly divided into the three superorders Acrothoracica, Thoracica, and Rhizocephala.

Here at Kidadl, we have carefully created lots of interesting family-friendly animal facts for everyone to discover! Learn more about some other arthropods including giant African millipede, or flatworms.

You can even occupy yourself at home by drawing one on our barnacles coloring pages.

Barnacle Facts

What Did They Prey On?

Plankton, detritus

What Type of Animal were they?

Suspension feeders, parasitic

Average Litter Size?


How Much Did They Weigh?


What habitat Do they Live In?

marine environments, on other animals like whales, turtles, fishes, or crustaceans

Where Do They Live?


How Long Were They?

0.5-1 in (1.2-2.5 cm)

How Tall Were They?

0.5-1.5 in (1.2-4 cm)







Scientific Name

Semibalanus balanoides and Balanus glandula (Acorn Barnacles), Pollicipes polymerus, Pollicipes pollicipes, and Lepas anatifera (Gooseneck Barnacles)

What Do They Look Like?

White, gray, yellow, pink, green, and brown

Skin Type

Calcareous shell

What Are Their Main Threats?

limpets, mussels, snails, humans, whelks, starfish

What is their Conservation Status?

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Written by Moumita Dutta

Bachelor of Arts specializing in Journalism and Mass Communication, Postgraduate Diploma in Sports Management

Moumita Dutta picture

Moumita DuttaBachelor of Arts specializing in Journalism and Mass Communication, Postgraduate Diploma in Sports Management

A content writer and editor with a passion for sports, Moumita has honed her skills in producing compelling match reports and stories about sporting heroes. She holds a degree in Journalism and Mass Communication from the Indian Institute of Social Welfare and Business Management, Calcutta University, alongside a postgraduate diploma in Sports Management.

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