Pacific Acorn Barnacle
Balanus glandula
They produce a natural underwater cement so incredibly strong that dentists and engineers have studied its chemical makeup for medical and industrial adhesives.
- Scientific name
- Balanus glandula
- Taxonomy
- Animalia › Arthropoda › Hexanauplia › Balanomorpha › Balanidae › Balanus
- IUCN Red List status
- Least Concern
- Population trend
- stable
- Biome
- aquatic
- Habitat
- Rocky intertidal zones, docks, and hard substrates in the high-to-mid tide levels.
- Diet
- Plankton and organic detritus filtered from the seawater.
- Range
- Pacific Coast of North America, Alaska, California, Baja California
- Size
- Up to 2.2 cm (0.87 inches) in diameter
- Lifespan
- Up to 5-10 years
- Active
- diurnal
- Threats
- Ocean acidification, coastal development, oil spills, and extreme heatwaves during low tides.
- Safe to approach?
- Harmless, but their calcified shells are razor-sharp. Wear thick-soled water shoes when exploring rocky tide pools to avoid painful cuts. If scratched, wash the wound immediately with fresh water and soap, then apply antiseptic to prevent marine bacterial infection.
Acorn barnacles ( Balanus glandula ) are one of the most common barnacle species on the Pacific coast of North America, distributed from the U.S. state of Alaska to Bahía de San Quintín near San Quintín, Baja California. They are commonly found in intertidal waters on mussels, rocks and pier pilings.
Photo: Nelson Balcar, CC-BY, via iNaturalist
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