Animal profile

By-the-wind Sailor

Velella velella

HydrozoaOpen-ocean surface waters

Field profile

Velella velella is a small blue hydrozoan that floats at the sea surface with a stiff triangular sail set across an oval float. It drifts entirely at the mercy of wind. Mass strandings can leave millions of individuals along a shoreline.

Published field notes

2023-04-15

By-the-wind Sailor

By-the-wind sailors come in left and right forms

The sail sits diagonally across the float, and populations contain mirror-image individuals angled the opposite way. Each form sails at an angle to the wind in the opposite direction, so a single onshore blow can strand one form while the other stays at sea.

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