Gossamer worms live in the midwater zone of the ocean along with many other polychaete worm species. They are transparent as are so many of the creatures of this twilight zone between the surface and the seafloor. Their transparency helps make the worm harder for predators to spot. There are about 60 identified species of gossamer worms ranging in size from a few centimeters to up to 60 centimeters (2 feet) long.
These worms are strong, fast-swimming predators feeding on other small worms, tunicates and fish larvae. Researchers at the Monterey Aquarium Research Institute(MBARI) including our Featured Scientist Karen Osborn, have studied their swimming behavior. One of the scientists, Joost Daniels, said of gossamer worms, “When you see them swimming around, it looks like a little dance—they swim forwards, backwards, make these quick turns, and have all these little legs moving rapidly.”
Researchers looked at hours and hours of videos of gossamer worm swimming. These worms don’t have the hair-like chaetae that define polychaetes. Instead they have paddle-shaped fleshy legs (parapodia) that beat in sequence, moving the worm forward. The videos revealed the worms contract and spread the fleshy ends of their legs just like swimmers open and close their hands when doing the freestyle. Watch this video from MBARI.
Dancing & Glowing Worms
Like so many animals in the midwater, gossamer worms are bioluminescent. When attacked, the worms emit a “ …swirling constellations of golden glowing spots to distract predators.” The glowing material can last for several seconds in the water. Most animals in the deep emit a blue-green light; it’s rare to see yellow light. Scientists don’t know why most gossamer worms make golden light instead of blue-green. A scientist at MBARI says, “It certainly is incredible to see.“
There are many species of gossamer worms in Monterey Bay. Scientists expected to find seven species, but so far have identified 23. Scientists at MBARI see different body types and behaviors. Karen Osborn said that wasn’t surprising to her. Maybe they are specialized to feed on different prey or to live at different depths.
