Cnidaria · cnidarians

Portuguese man o' war

Physalia physalis

Physaliidae · man o' warsIUCN: Not evaluated
Portuguese man o' war
Photo: Image courtesy of Islands in the Sea 2002, NOAA/OER. · Public domain · Wikimedia Commons · resized

A colonial siphonophore made of specialized zooids, held up by a gas-filled float.

Fun factIt isn't a single animal. It's a colony of specialized individuals that can't survive alone.

Waters
Worldwide, Northeast US
Depth zone
Open-ocean surface waters
Diet
Small fish & larvae
Size
Float up to 30 cm; tentacles to 30 m

Classification

Cnidaria › Hydrozoa › Siphonophorae › Physaliidae

  1. Kingdom Animalia animals
    • Many-celled organisms that eat other living things for energy (heterotrophs)
    • Cells have no cell walls
    • Most can move at some stage of life
  2. Phylum Cnidaria cnidarians
    • Radially symmetric bodies with one opening that is both mouth and anus
    • Stinging cells (cnidocytes) fire tiny harpoons (nematocysts)
    • Two body forms: an attached polyp and a swimming bell (medusa)
  3. Class Hydrozoa hydrozoans
    • Mostly small, often colonial animals with both polyp and medusa stages
    • Medusae have a shelf of tissue (velum) under the bell
    • Includes hydroids, fire corals, and siphonophores
  4. Order Siphonophorae siphonophores
    • Floating colonies of specialized individuals (zooids) that work as one animal
    • Different zooids swim, feed, sting, or reproduce
  5. Family Physaliidae man o' wars
    • Siphonophores with a gas-filled float (pneumatophore) at the surface
    • Long trailing stinging tentacles
  6. Genus Physalia
    • Species in the same genus are very close relatives and often look alike.
  7. Species Physalia physalis Portuguese man o' war

Closest relatives in the guide