Changing Planet

For a Nearly Hundred-foot-long Jellyfish, It’s Christmas All Year

This Apolemia siphonophore (colonial jelly) was photographed by the Monterey Bay Aquarium Research Institute using an underwater robot about 3,400 feet below the surface of Monterey Bay. Photograph 2005 MBARI

Like the fuzzy tinsel used to deck Christmas trees, this jellyfish relative—known as Apolemia—looks soft enough to cuddle. But keep in mind that it’s also armed with tiny poison-filled needles, which it shoots into animals unfortunate enough to blunder into it.

Apolemia is part of a group called the siphonophores, which are related to jellyfish. The Portuguese Man-of-War is perhaps the most well known siphonophore.

In general, animals in this group are made up of one or more “bells,” which they use to propel themselves through the water. The bells are attached to a train of stomachs, from which hang thin tentacles coated with batteries of stinging cells. All of these parts are connected by one digestive tract.

Siphonphores can be anywhere from a few inches (centimeters) to over 100 feet (30 meters) long. Apolemia and another group, Praya, are so long that they’ve been known to show up on sonar.

These animals are ambush predators, lying in wait with their tentacles extended. When prey like small fish or tiny crustaceans brush against the tentacles, stinging cells fire, harpooning the prey. The tentacles contract, bringing the wriggling victim to a waiting stomach to be digested.

Some siphonophore species drift through the water with their tentacles hanging straight down from their body stalk—like a diaphanous curtain of death. Other species twist and curl themselves into shapes—like spirals or Js—in order to deploy their tentacles.

Certain species actively set their “nets” by swimming in certain directions. As a siphonophore swims, it can relax part of its body, enabling it to drag behind the rest of the animal. Think of pulling one end of a ball of yarn free from the rest.

As the siphonophore swims in a circle or spirals through the water, its body arranges itself into a J or some other formation behind it.

Gravity and currents can undo those shapes, so every now and then, the animal must gather its net and swim to another location to set its trap.

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Jane J. Lee is a news writer and editor at National Geographic.
  • kate

    Okay, siphonophores are way the hell cooler than this article gets into. First off, they’re related to jellyfish only in the same way all mammals are related, they’re a distinct subclass of Hydrozoa. Second off, although they act like individuals they’re actually colonies of hyper-specialized zooids that depend on one another to survive. While most animals are made up of one organism with specialized systems of organs that evolved over millions of years, siphonophores took a radically different evolutionary path, with organized colonies of interdependent individuals each specializing in one aspect of survival. I don’t think there’s any other type of creature that can challenge our notions of what an animal is, or the wild paths evolution can run down, than the siphonophore.

    Also, they look like something Lovecraft had nightmares about. Not tinsel.

  • kate

    *more than the siphonophore. Phooey.

  • Christian Duerig

    Complexity within the very simple.
    Super-organism as we, are made of 10 exponent 13 different cells and a collection of 10 exponent 14 microbes. Take those microbes away and what left behind, will die within days. Even a super-organism is a colony of special life forms.
    The researcher may find microbes within the siphonophores as well. It seems that live exists only in colonies. Individuals are dying away if they do not find a partner to build up …..
    You may guess what.
    Thank you very much for this beautiful story !

  • Robert C Brooke

    Incredible.It doesn’t look like my idea of a siphonophore.Siphonophore brings to mind the image of a Potuguese man of war or sailor by the wind.

  • Tammy Law :ps200-student8years old

    Wow!Acording to the text It,s incredible and also what is a siphonophore ?

  • charles Brewer-Carias

    Could someone else repeat the explanation, this speaker is really a mess modulating the words and it becomes berely understable for most of the non english born speakers (I believe)

  • charles Brewer-Carias

    Please pronounce better your english. Be more international. You sound too local, rural, wich is good if you are selling Donuts, but not delivering information to an international audience.

  • Nauman

    Does not it stung the person who took its photos? I think the picture is either magnified or unreal?

  • Jane Lee

    The photograph above was taken by a remotely operated vehicle—so no one was in the water to sting.

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