Why do barnacles attach permanently?
Show answer & explanation
Answer: Filter-feeding requires stability
Conserving energy for reproduction — Wrong. Staying attached saves energy, but the primary reason is their feeding strategy—they need to be stationary to filter-feed effectively.
Filter-feeding requires stability ✓ — Correct! Adult barnacles secrete the strongest natural glue known to attach permanently to rocks, ships, whales, etc. They extend feathery legs (cirri) to filter plankton from passing water. Being stationary in current-rich areas maximizes food capture. They're crustaceans (related to crabs) that evolved to become sessile filter-feeders!
Hiding from mobile predators — Wrong. Barnacles have hard protective shells for defense. Permanent attachment is about filter-feeding efficiency, not predator avoidance.