David Fleetham / Pebble crab (Leucosia pubescens) can bury itself completely in the sand to escape predators, Komodo, Indonesia.

Nick Upton / Two Montagu's crabs (Xantho hydrophilus) competing for a crevice to hide in within a rockpool, with a young Velvet swimming crab (Necora puber) moving away nearby, Cornwall, England, UK, September.

Nick Upton / Two Montagu's crabs (Xantho hydrophilus) competing for a crevice to hide in within a rockpool, Cornwall, England, UK, September.

Pascal Kobeh / Boxer / Pompom crab (Lybia tessellata) holding its eggs on hard coral, Manado, Indonesia. Sulawesi Sea.

Pascal Kobeh / Boxer / Pompom crab (Lybia tesselata) with eggs underneath, Manado, Indonesia. Sulawesi Sea.

Franco Banfi / Button crab (Paractaea monodi) on encrusting red sponge, Ponza Island, Italy, Tyrrhenian Sea, Mediterranean