Barnacles have the most impressive penises in the sea – a barnacle’s penis can be 8 times longer than the barnacle’s entire body. Barnacles are well-endowed because they’re cemented in place – in order to advance the species, they need to, um, “visit” their neighbors. (That’s also why barnacles are simultaneous hermaphrodites that both give and receive the glorious gift of crustacean life. Separate sexes wouldn’t work, since the only neighbor in reach could be the same sex.)
Graduate student Christopher Neufeld and Dr. Richard Palmer from the Department of Biological Sciences at the University of Alberta have shown that barnacles appear to have acquired the capacity to change the size and shape of their penises to closely match local wave conditions.
When wave action is light, a longer (thinner) penis can reach more mates, but at times of higher wave action, a shorter (stouter) penis is more manoeuvrable in flow and therefore can reach more mates.
It’s not the size of the barnacle penis, it’s the motion in the ocean! Clearly, this calls for a viewing of that classic of crustacean pornography, “Barnacles Tell No Lies.”