D I D YOU KNOW?
and laying eggs at the same time, with the animal that started the chain acting like a female and the last to the party a male.
But when sea hares stretch out to feed, they start making some kind of sense. How they get their name is immediately apparent. On top of their ‘head’ are a pair of tentacles called rhinophores, which stick up like bunny ears. Together with another pair of oral tentacles closer to the mouth and a couple of tiny beady eyes inbetween, these form a sensory array used to detect food, mates and predators.
Meanwhile, on their back is a frilly, upside-down skirt made up of winglike appendages called parapodia. Hidden under these is a soft internal shell, the gill chamber and a structure known as the siphon, which sucks water in and out, allowing the animals to breathe.
Sea hares slide around rockpools, grazing in a slug-like manner. They use their radula (equivalent to a tongue, but wielded like a file) to scrape away mouthfuls of seaweed. However, these creatures represent a good mouthful of protein to many a potential predator, from crabs and lobsters to anemones and
The sticky sleight of hand with which sea hares confuse predators is called phagomimicry. fish. Soft and squishy they may be, but defenceless they are not.
If you were to pick up a sea hare, you might find your hands covered in a spectacular purple substance. Underwater, the cloud of ink they produce must undoubtedly serve as a visual warning, yet it also contains a special kind of molluscan alchemy. The ink is made by one gland, while another produces opaline. This secretion is squirted at an attacker using the exhaling siphon.
When mixed with seawater, opaline becomes a gloopy, sticky compound – imagine getting this all over your gills or mouthparts! Initially, the gunk becomes a super-stimulus to crustacean predators, who think that the sticky soup is their prey, rather than the sea hare itself. Shortly afterwards, secondary effects kick in. The sensory organs with which the crustaceans located the ‘prey’ become blocked.
Better still, the sea hares’ glandular secretions react with each other to form more nasty compounds, including sodium peroxide and carboxylic acids, which act as extra deterrents. One squirt of this foul chemical cloud is usually enough for a sea hare to slink away unharmed.