About Siphonophores

A siphonophore is much more than the sum of its parts. In fact, none of its parts could function on their own. Each siphonophore is actually a colony of individual parts, called “zooids”, which are produced as the siphonophore grows, and stay connected together. Some form rope-like  chains that can grow longer than a whale. Each zooid has a distinct job in this colony: some catch prey, while others digest it, and still others reproduce, swim, and keep the colony upright. The result is a biological marvel that makes us wonder just what it means to be an “individual”!

Scientists have found over 175 species of siphonophores, in habitats ranging from near-coastal regions to the ocean twilight zone and the sea floor. Deep water species are often dark orange or red in color, and are bioluminescent— glowing green, blue, and sometimes red—a function that likely attracts prey. 

Siphonophores use their numerous tentacles to sting and trap their prey, injecting a toxin to incapacitate their prey.  You may be familiar with this if you’ve ever touched a Portuguese Man O’ War! These traits often lead people to confuse siphonophores with their jellyfish cousins—but they are a distinctly different group.

Quick Facts

Common NameSiphonophore
Other NamesNo common names except for the Portuguese Man O’War.
Sizelargest ever recorded measured 15 m (49 ft) in diameter and 47 m (154 ft) long
DiscoveryCarl Linnaeus discovered and described the first siphonophore, the Portuguese man o' war, in 1758.
Eats what?Copepods, small crustaceans and fish
Eats how?Tentacles sting prey and pull it into multiple mouths. Some species emit red light and mimic the prey’s swimming habits to bring them closer.
Is eaten by?Sometimes Phromina (pram bug) will hollow out part of a siphonophore for a house.
BioluminescenceDifferent species bioluminesce