A highly specialized group of brittle starfish, Basket stars are named for their multi-branched arms, which, when extended, look much like an elegant basket. Some of the largest, oldest specimens have thousands of branchlets on their bodies. Found in a wide range of habitats, from tide pools to deep beneath the sea’s surface, these creatures are fascinating. Let’s take a closer look.
Basket Star Basics
Like most other starfish, basket stars have arms that radiate from a central disc-shaped body. Unlike many of their brittle star relatives, these starfish tend to be stationary, sometimes staying in a single place for years at a time so long as they are left undisturbed and the food supply is good; they are often mistaken for small coral trees, and unfortunately, they are sometimes plucked up and taken as souvenirs. Their close alliances with soft corals and sponges adds to this illusion; but, once you’ve seen a few basket stars, you’ll find that spotting them again in the future is a snap.
Basket stars and other starfish have no blood in their bodies. Instead, they achieve gas exchange via a water vascular system. They recover well from injury; if they lose an arm or even suffer the loss of several arms, they can regenerate their body parts fairly quickly.
As with other echinoderms, different basket stars enjoy different habitats. Some prefer to live on rocky substrate, while others prefer sandy stretches with little topographical relief. They are found in many different parts of the world, with most of the largest specimens living at depths below 30 feet. Incredibly, these animals have been documented to live for as long as 35 years; it is presumed that deep sea basket stars get to be even older than their shallow-water dwelling cousins.
These animals can grow to be quite large, with a single arm extending for more than two feet when full-grown. Sometimes hiding by rolling their appendages into tight balls, they prefer to feed in dark conditions. Those that dwell in the open can usually be seen fully extended on night dives, while cave dwelling basket stars and those that have secreted themselves beneath overhangs and in other twilight environments can be seen feeding during daylight hours.
To eat, basket stars simply collect algae and zooplankton. Their arms and branchlets are covered in minuscule hooks that make trapping prey easy; once prey is captured, the branchlets roll up into small knots, then mucosal glands secrete a substance that stuns prey. Once an arm has captured a few bites of food, that arm rolls under, toward the basket star’s mouth, which is located on its ventral surface. After food has been deposited, the arm comes back up and branches out. You can tell whether a basket star is getting enough to eat by looking at its’ center. If it looks puffy and inflated, then the animal is getting plenty of food. If the central disc has a deflated look, then the basket star needs to feed or it may starve.
Basket stars are abundant in many different reef environments and are usually a creamy white to pale tan color. While they face no direct threats, they are subject to habitat loss and suffer when marine environments become polluted; with careful conservation, we can continue to enjoy these magnificent creatures in times to come.