The rock protects them from predators on all sides except the opening of the hole, and the spines guard that.

When an individual finds an especially good fitting hole, it can brace its spines against the sides of the rock to resist being pulled out of its niche.

[4] Crowned sea urchins are nocturnal, foraging within a few meters of their shelters, to which they return at dawn.

[8] Crowned sea urchins are gonochoric, which is to say that there are two sexes, and each individual is either male or female.

Spawning takes place on a monthly cycle that may be tied to tidal rhythms.