### Identification Commonly known as the "By-the-Wind Sailor," *Velella velella* is a master of maritime engineering. Look for a firm, oval float—typically 2 to 7 cm long—of a striking, deep electric blue. Atop this disc sits its most defining feature: a stiff, translucent, triangular sail made of chitin. While often mistaken for the Portuguese Man o' War, the *Velella* is smaller, flatter, and lacks the balloon-like bladder and dangerously long, trailing tentacles of its larger cousin. Its short, fringe-like tentacles hang just millimeters below the surface, appearing like a delicate sapphire ruff.
### Habitat & Range These are true pelagic voyagers, inhabiting the "pleuston"—the thin sliver of world where the ocean meets the atmosphere. They are found globally in warm and temperate waters. While they spend their lives in the open sea, beachcombers are most likely to encounter them during "mass strandings," when persistent onshore winds push thousands of these "blue fleets" onto the sands of the Pacific Coast of North America or the Atlantic shores of Europe.
### Behaviour The *Velella* is not a single animal, but a colonial hydroid—a cooperative of specialized polyps functioning as one. They do not swim; they sail. An observer will notice that the sail is set diagonally across the float. Remarkably, they exhibit "handedness": some populations have sails angled to the right, others to the left. This dimorphism ensures that a single wind pattern won't drive the entire global population onto the shore at once.
### Diet Trailing beneath the float are specialized feeding polyps equipped with stinging cells called nematocysts. As they drift, they act as a living drift net, snagging fish eggs, copepods, and microscopic zooplankton. While their venom is lethal to tiny prey, it is generally too weak to penetrate human skin, though one should still avoid touching their eyes after handling them.
### Fascinating Fact The *Velella* is a "solar-powered" sailor! Beyond hunting, they host symbiotic intracellular algae called zooxanthellae within their tissues. These algae photosynthesize, providing the colony with a supplemental source of carbon—essentially allowing the animal to eat the sun while it cruises the currents.