The Portuguese man-of-war is actually a floating colony of individuals called polyps that are all dependent on each other for survival. One large polyp forms a gas-filled, blue, translucent body that floats above the surface. Long tentacles that dangle down in the water are specialized to detect and capture prey. Other polyps are specialized for digesting prey once it is captured.

Scientific name: Physalia physalis
Size: tentacles up to 165 feet long
Habitat: warm water environments of the Pacific and Indian oceans
Diet: algae, plankton, small crustaceans
Characteristics: gas-filled, purplish-blue float; tentacles; moves using the crest of the float
Significance: predator of a range of marine organisms; some fish and sea turtles prey on it

Image credits: main image: courtesy of Dr. Thomas, M. Scott, Florida Geological Survey.