Bence Mate / Grey heron (Ardea cinerea) squabbling, Lake Csaj, Kiskunsagi National Park, Pusztaszer, Hungary. February.

Robert Thompson / Dog whelk (Nucella lapillus) and Common barnacle (Semibalanus balanoides) on rock. Mill Quarter Bay, Killard Point National Nature Reserve, Strangford, County Down, Northern Ireland. February.

Nick Upton / Dog whelk (Nucella lapillus), a predator of barnacles, on rocks encrusted with Common barnacles / Northern rock barnacles (Semibalanus balanoides) exposed at low tide, with seaweed, a rock pool and th...

Scott Leslie / Common Northern Whelk (Buccinum undatum) tending egg mass, Maine

Ingo Arndt / Common Northern Whelk (Buccinum undatum) shell length is approx seven centimeters, Helgoland, Germany

Ingo Arndt / Hermit Crab (Anapagurus laevis) in a snail shell from a Common Northern Whelk (Buccinum undatum) approximate length is nine centimeters, Helgoland, Germany

Ingo Arndt / Hermit Crab (Anapagurus laevis) in a snail shell from a Common Northern Whelk (Buccinum undatum) approximate length is nine centimeters, Helgoland, Germany

Ingo Arndt / Hermit Crab (Anapagurus laevis) in a snail shell from a Common Northern Whelk (Buccinum undatum) approximate length is nine centimeters, Helgoland, Germany

Ingo Arndt / Hermit Crab (Anapagurus laevis) in a snail shell from a Common Northern Whelk (Buccinum undatum) approximate length is nine centimeters, Helgoland, Germany

Duncan Usher / Flat Topshells (Gibbula umbilicalis), Common Northern Whelk (Buccinum undatum), and Common Periwinkle (Littorina littorea) shells