Barnacles | Facts, Diet, Habitat & Pictures

Barnacles | Facts, Diet, Habitat & Pictures

Barnacles Overview


Barnacles are small, hard-shelled marine crustaceans that attach themselves to various surfaces. They appear as a series of overlapping plates or shells, resembling miniature volcanoes or cones. Their outer shells are often gray, brown, or white, blending with their surroundings.

Barnacles have multiple feathery appendages called cirri that extend from their shells, used for feeding and respiration. When submerged in water, these appendages filter small particles from the water column.

Origins And Evolution

Barnacles have ancient origins dating back to the Early Cambrian period, over 500 million years ago. They belong to the class Cirripedia, which is part of the larger arthropod phylum. Their evolutionary journey includes transitions from free-swimming larvae to sessile, shell-encased adults.

Over millions of years, they have developed specialized adaptations for their unique lifestyle, such as their calcareous shells and feathery appendages for filter feeding. They have diversified into various species, each adapted to different marine environments, including intertidal zones, deep-sea habitats, and the shells of other marine organisms.

Behavior and Lifestyle

Barnacles are predominantly sessile organisms, meaning they attach themselves permanently to various surfaces, such as rocks, ship hulls, or the shells of marine creatures. They employ adhesive substances and a tough calcareous shell to firmly anchor themselves.

Barnacles are filter feeders, extending their feathery appendages, known as cirri, into the water to capture tiny planktonic organisms and particles as the water flows past. They are most active during high tide when their feeding appendages are submerged.

Barnacles can adapt to changing environmental conditions by adjusting the timing of their feeding and reproductive activities.

Scientific Classification

  • Kingdom: Animalia (Animals)
  • Phylum: Arthropoda (Arthropods)
  • Subphylum: Crustacea (Crustaceans)
  • Class: Maxillopoda (Maxillopods)
  • Subclass: Thecostraca (Thecostracans)
  • Order: Sessilia (Sessile Barnacles)


  • Intertidal zones
  • Rocky shores
  • Ship hulls
  • Piers and docks
  • Submerged rocks and reefs
  • Shells of marine creatures
  • Underwater structures
  • Mangrove roots
  • Offshore oil rigs
  • Deep-sea habitats

Fast Facts

  • Scientific Name: Cirripedia spp.
  • Habitat: Intertidal Zones
  • Diet: Filter Feeder
  • Physical Features: Hard Shells
  • Nocturnal: Tidal Rhythms
  • Solitary: Colonial Attachment
  • Unique Order: Cirripedes
  • Lifespan: 2-3 years
  • Conservation Status: Not Assessed
  • Fun Facts: Anchored Crustaceans

Physical Characteristics

  • Color: White Exoskeleton
  • Skin Type: Hard Shells
  • Top Speed: Stationary Attach
  • Lifespan: 2-3 Years
  • Weight: Lightweight Shell
  • Length: Varied Sizes
  • Age of Sexual Maturity: Variable Times
  • Age of Weaning: Larval Stage

Barnacles FAQs

Q: What are barnacles?

Ans: They are marine crustaceans that live attached to surfaces and are known for their hard, calcareous shells.

Q: How do barnacles attach themselves to surfaces?

Ans: They use a cement-like substance to adhere to rocks, ships, piers, and other submerged structures.

Q: Do barnacles move or swim?

Ans: They are sessile, which means they are permanently attached and do not move or swim once they settle.

Q: What do barnacles eat?

Ans: They are filter feeders, using their feathery appendages (cirri) to capture plankton and other tiny particles from the water.


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