This video shows how sea urchin larvae drift through the ocean, feeding and growing the juvenile urchin form inside their body.
Once they reach a suitable location they turn themselves inside out, pulling their tube feet from within to latch on to rocks. Within hours they can look like an adult sea urchin.
The larval and adult forms of sea urchins have completely different body structures. As a larva they have two equal halves, like humans – but as an adult they have fivefold radial symmetry.
If they survive this turbulent journey, sea urchins might live over a century!
Deep Look is a ultra-HD short-video series created by KQED San Francisco and presented by PBS Digital Studios.