Biology/Natural History: L. hexactis
is known to cling very tightly to rocks and it has the ability to conform closely to irregularities in the surface. It is a carnivore and feeds on sea cucumbers, littorine snails, limpets, chitons, small mussels, barnacles, and other small animals, including dead animals. L. hexactis
often selects large, hard to capture prey that is often rich in calories. This type of prey supplies most of the sea star's energy. It is often in direct competition with the much larger sea star, Pisaster ochraceus
for food. Breeding occurs from November to April in the Puget Sound. The eggs are yellow, yolky, and about 0.9 mm in diameter. A unique feature of this species is that the broods of eggs (ranging from 52 - 1,491 eggs, variable based on the size of the female) are held by the female in the region of the mouth below the central disk. Because of this, brooding females cannot flatten themselves against the substratum and are only anchored by their outermost tube feet. Unfortunately, they are often dislodged by the waves, losing their eggs. It is necessary for the female to clean the egg masses, and if she does not do this then the eggs quickly die. The presence of the eggs blocks the female's mouth and she will not feed while brooding, even if there is food readily available. The development of the embryos is direct and L. hexactis
individuals will reach maturity within 2 years. Experiments with the behavior of L. hexactis
have shown that if the nerve ring is cut at two opposite points, then the animal will walk apart until fission occurs.
Leptasterias hexactis is fleshy, with large papulae and a stronger, coarser skeleton than is Henricia leviuluscula, another intertidal seastar of similar size. It seems to rely much less on its madreporite to take up seawater for maintaining its tissue fluid balance. It probably uses osmotic uptake of fluid through the papulae instead (Ferguson, 1994).