大象传媒

Barnacles catch food by sweeping their legs through the water. But the long hooked things probing around are penises that are depositing sperm into neighbours. As barnacles are male and female at the same time, there's a good chance of fertilisation and the production of millions of larvae that are released into the plankton. If they survive long enough, they might find a bare surface to settle on, even a recent wreck. Once they are cemented to the deck there's no second chance to change position as they grow into mini-adults. Although their bodies are protected by hard plates, they are still vulnerable. The shanny is one of the few fish adapted to feed on barnacles, particularly their exposed legs. Any vacant spaces will soon be filled by more barnacles.