Head to head
Blue Button vs By-the-Wind Sailor
The blue button and the by-the-wind sailor are both colonial organisms that drift across the ocean surface and are frequently mistaken for jellyfish, but one relies on a rigid sail to catch the wind while the other has no steering mechanism at all.
| Blue Button | By-the-Wind Sailor | |
|---|---|---|
| Scientific name | Porpita porpita | Velella velella |
| Classification | A colonial hydrozoan | A colonial organism (chondrophore) |
| Shape | A flat, disc-shaped float ringed with tentacles | A flat float topped with a rigid diagonal sail |
| Movement | Drifts with wind and current | Propelled by its sail, pushed by the wind |
| Sting | Generally mild to humans | Too weak to be felt through human skin |
| Colouring | Blue disc with short tentacles | Vivid blue, from carotenoid pigments |
| Range | Warm oceans worldwide | Warm and temperate oceans worldwide |
| Conservation status | Not Evaluated | Least Concern |
Blue Button vs By-the-Wind Sailor: common questions
What is the key difference between a blue button and a by-the-wind sailor?
The by-the-wind sailor has a rigid, fixed-angle sail that actively catches the wind to propel it across the ocean surface, while the blue button has no such sail and drifts passively with wind and current alone.
Are the blue button and by-the-wind sailor dangerous to touch?
Neither poses much danger to people; the blue button's sting is generally mild, and the by-the-wind sailor's stinging cells are typically too weak to even be felt through human skin.
Are the blue button and by-the-wind sailor related?
Yes, both are colonial organisms called chondrophores, a group related to but distinct from true jellyfish, and both are often mistaken for small jellyfish by beachgoers.