Georgette Douwma / Boxer Crab (Lybia tessellata) with sea anemones in its claws for defense. Lembeh Strait, North Sulawesi, Indonesia.

Steven David Miller / Great bowerbird (Chlamydera nuchalis), male showing off treasures whilst female inspects bower. Lake Argyle, Kununurra, Western Australia.

Guy Edwardes / Portland Bill Lighthouse, Isle of Portland, Dorset, England, UK. November 2015.

Guy Edwardes / Porth Nanven, Cot Valley, Porth Nanven, Cornwall, England, UK. September 2017.

Nick Upton / Common prawns (Palaemon serratus) and a Rock goby (Gobius paganellus) feeding on a dead Montagu's crab (Xantho hydrophilus) in a rockpool, Cornwall, England, UK, September.

Olga Kamenskaya / Pebbles reflected in the water surface at mouth of Sheryldy river, Lake Baikal, Siberia, Russia. September

Alex Mustard / A shoal of Golden grey mullet (Liza aurata) swim in the surf breaking on the shore of El Hierro Island. Canary Islands, Spain. East Atlantic Ocean.

Floris van Breugel / Glass beach at sunset - a former dump site, in which the glass has now become pebbles of sea glass. MacKerricher State Park. California. USA. January 2013

Theo Bosboom / Cushion pink (Silene acaulis) in highlands, A?xarfjardarheidi, Iceland, June

Sandra Bartocha / Waves of Baltic Sea washing over and polishing coloured pebbles, Markgrafenheide, Mecklenburg-Vorpommern, Germany, January

Laurie Campbell / Cliff scenery at North Hoy, Hoy, Orkney, Scotland, July 2008

Colin Varndell / Adder (Vipera berus) basking on pebble beach. Abbotsbury, Dorset, UK, March.