This sea star is commonly found under rocks in the intertidal zone. It has between 6 and 9 arms, but as its common name suggests, it usually has 8. It is fissiparous, which means it can reproduce by splitting in half, with each half regrowing the missing portion and becoming a fully functioning new animal. For this reason, it is often seen with 4 arms, which may also help to explain its common name. Colouration can vary, and while usually a grey or tan with reddish blotches, it can also be found in other colours, such as pink, black or orange. In addition to the number of arms, this animal can be distinguished from similar long-armed species by its dense coverage of relatively small spines.
