Not quite a Man O'War

Image via Wikimedia

Velella is the scientific genus of this amazing colonial animal. Firstly; By-the-wind Sailor, what a wonderfully romantic name!  They get it from their lifestyle which is similar to our very own Portuguese Man o’ War, although they are much smaller and clearly a lot less famous. Sailors reach about 7 centimetres across and have quite a tough, rigid sail to harness the wind. It’s actually made of chitin, like insect exoskeletons. The sail I mean, not the wind. Like the Man o’ War, individuals have sails that bear either left or right into the wind so that when thousands are washed up on a beach, another few thousand have been sent in the opposite direction. When you have one sail and no oars or boat propeller I suppose something like that is necessary. A 50-50 chance is better than none at all! Surrounding the sail are rings of air filled tubes to provide buoyancy.

Image via Wikipedia

Despite the lovely name and care-free (until you hit the rocks) life style, By-the-wind Sailors are Cnidarians, which means they are meat eating, stinging creatures. In this case the tentacles are short, only about 1 cm long, and hang down below the edge of the disc and into the sea. They feed on tiny plankton of various kinds and seem to be completely harmless to humans, clearly a terrible disaster for their chances of fame. Why are they harmless? Likely because their stinging cells are too short to penetrate our protective skin.

It looks like most people consider By-the-wind Sailors to be made up of hydroid colonies, again, much like the Portuguese Man o’ War. Instead of one, big animal, it’s actually made up of lots of little ones that work together. It looks like others disagree and prefer to see it as something more like a floating, upside down Sea anemone with a sail on its foot. The entire concept of a colony of animals living as one is amazing and a modality us humans should learn from.

Image Wikipedia

Either way, By-the-wind Sailors are all either male or female. When they mate, they first produce thousands of tiny larvae that are free flowing plankton. These are about 3 mm across and are slightly brown because of their friends; inside their bodies are tiny microalgae that can gain energy from the Sun and provide some to their host. They are effectively paying for bed and board, which is nice of them. Eventually, the jellyfish will release sperm or eggs into the water to create new By-the-wind Sailors. It is a pretty odd life cycle, but then Cnidarians are utterly immersed in oddity so we’ll just have to get used to it.

These are rather common finds along the beaches in the late summer and fall. Loads of them get washed up all along the West coast of the US every year and they’ve even done the same in good ol’ Blighty. They look lovely with their rich, blue colours and concentric circles, yet there doesn’t seem to be great deal written about them. Shame. Looks like the Portuguese Man o’ War has stolen all the limelight!