Yesterday, I went for a stroll along Manly beach, north of Sydney. A line of beached Bluebottle jellyfish ran along the length of the beach.

(The only bird in this post is that little Silver Gull, peacefully asleep next to the stingers.)

Bluebottles are also called Pacific Men-of-War, I guess because the floating part looks a little like a ship at sail. Viewed close up, bluebottles are quite beautiful.

On top is a bag formed of gas-filled tubules that keep the bluebottle afloat and upright. Here’s another bluebottle, with a purple tinge on the top ridge of the floater:

Walking along the beach was a little tricky, because we had to dodge the bluebottles and their long, stinging tentacles that stretched out across the sand.:

Even when a bluebottle is dead, the tentacles can still give you a nasty sting. Tens of thousands of Australians are stung each year. Luckily, the stings of the Bluebottles found on the non-tropical, east coast of Australia are generally not fatal, though they are very painful.

Although we call them jellyfish, a bluebottle is in fact not a jellyfish. Each bluebottle is actually four different types of animals living together as a colony. There’s the creature that forms the gas-filled bag on top, keeping the jellyfish afloat. A second type of creature provides the tentacles, which sting the jellyfish’s prey and then draw it up to the digestive polyps, which are the third type of creature. The fourth creature provides the reproductive system.

A group of bluebottles is called an armada, like a fleet of ships. Mass beachings happen when the wind blows the bluebottles ashore. A weird thing I learned today: each bluebottle is built with its top part (the gas bag) positioned either to the right or to the left of the rest of the creature. Evidently, this affects the steering and helps to ensure that only half of an armada gets stranded on the beach when the wind forces them ashore.

It’s sad to see so many creatures perish. Still, I’m glad I had the opportunity to see them up close and learn about them.