EYE OPENER
Small but mighty
MAUI, PACIFIC OCEAN
Seen here are the delicate and flexible tube feet on the underside of a Leach’s sea star (Leiaster leachi). Tube feet are unique to echinoderms – that’s the group that includes starfish, sea urchins, sea cucumbers and brittlestars – and are operated via a water vascular system, which uses increasing and decreasing water pressure to extend and contract the appendages. In this way, a starfish can propel itself across the seabed, releasing and reattaching the tube feet in a coordinated fashion, creating a mesmerising pattern of motion.