Siphonophores: The clonal colonies that can grow longer than a blue whale

The largest animal on Earth is thought to be the blue whale, but these strange sea creatures can grow even longer — reaching up to 150 feet (46 meters) in length.

There are around 175 species of siphonophores living in the deep sea throughout all of Earth’s oceans, although not every species is found in each ocean. Many siphonophores are long and string-like, but some, like the venomous Portuguese man o'war (Physalia physalis), resemble jellyfish.

Although a siphonophore may look like a single animal, it is actually a colony made up of individual organisms called "zooids," which each have a distinct function within the colony despite being genetically identical. Some catch prey and digest food, while others enable the colony to reproduce or swim. An individual zooid cannot survive on its own because they specialize in one function, so they rely on each other to form a "body."