Praya dubia, also known as the Giant Siphonophore, is a hydrozoan that lives in the deep sea. Similar in appearance to a jellyfish, Praya dubia is a species of siphonophore, which is a colony made up of numerous organisms. As of 2014, Guinness World Records lists Praya dubia as the longest organism known to science.
Praya dubia, measuring between 100 and 160 feet long, consists of a dome-like nectosome, also called a swimming bell, and long tentacles. The long, thin tentacles contain cormidia, which have the capacity to sting. Praya dubia can immobilize and kill its prey and can give off a bioluminescent glow.
Each part of a siphonophore’s body is a highly specialized organism that has been adapted for a particular function, such as stinging, reproducing, food consumption or defense. Researchers believe this coordination and specialization among a siphonophore's parts is what makes zooids, a single part of a colonial animal, reliant on each other for survival.
Praya dubia’s existence has been known since the 19th century, but its length was a mystery until 1987, when a study was conducted by the Monterey Bay Aquarium Research Institute. Praya dubia is the type of siphonophore most frequently seen in Central California's aquatic bodies.