Our animals




LatinBalanidae sp.
Size2 cm
HabitatAlong shores on rocks and other hard surfaces

Not evaluated

LocationNorthern hemisphere

A sessile crustacean

A barnacle is a crustacean in the crab and lobster family. Unlike them, it remains stuck to the surface, which can be anything from rock to the underside of a boat.

Lives inside a house

The barnacle lives inside a white, volcano-like house with a door that consists of 2 moveable panels of calcium. These panels can be closed to prevent the barnacle from drying out at low tide.

Eats with its feet

A barnacle always lies on its back with its legs pointing up. The feet have evolved into feather-shaped fans, which serve as a ‘fishing net’. Using their feet, they can catch passing plankton, which they then eat.

Both male and female

The barnacle is what is known as a ‘hermaphrodite’ meaning that is simultaneously male and female. Barnacles live in large groups and by being a hermaphrodite the opposite sex is never far away. But the barnacle cannot fertilise itself.

Size does matter

Because barnacles lives attached to a surface, mating can be a bit of a challenge. The barnacle has sorted out this problem by having the longest penis in the world in relation to its overall size. It is several centimetres long: at least twice as long as its body. That means it can reach its neighbour.