The Freaking Awesome Feeding Habits Of A Feather Star

Feather stars are curious things. For staters, their arms are covered in feet. Long, wiggley feet that can move independently and terminate in something quite like a suction cup. They have several such arms and use them to swim, swishing half down to the seafloor and half up to the surface in an elegant ballet that slowly propells them through the water.

If they aren't swimming, a few extra appendages called cirri are holding them fast to a rocky outcrop so they can feed. From here they can gorge on all manner of tasty morsels (plankton and detritus drifting in the water). Feather stars raise their arms up into the current and catch food particles in a sticky mucous that covers their feet.

Once a few food particles have been caught, the foot furthest from the mouth bends down to the foot below it. This second foot wraps around the first and slides along it, scraping off the mix of morsels and mucus to form an appetising bundle that's passed along the arm.

This bolus, or ball of food, is then passed to the mouth along a grove in the centre of each arm, shuffled along by a current created by tiny hairs. Finally, when it reaches its destination, the ball of food is digested internally, providing the feather star with a scrumptious snack.

Images

1) A few feather stars in action (Antedon bifida). Credit: Bernard Picton via Wikimedia Commons

2) Feather stars have an upward-facing mouth. Here it is. Credit: Philippe Guillaume via Wikimedia Commons