Richard Du Toit / Aerial view of herd of Common zebra (Equus quagga) Makgadikgadi salt pans, Botswana

Richard Du Toit / Aerial view of Common zebra {Equus quagga} crossing the Makgadikgadi salt pans, Botswana

Alex Hyde / A millstone grit formation known as the 'Salt Cellar' on Derwent Edge, with Common Heather (Calluna vulgaris) in bloom, Peak District National Park, Derbyshire, UK. September.

Alex Hyde / A millstone grit formation known as the 'Salt Cellar' on Derwent Edge, with Common Heather (Calluna vulgaris) in bloom, Peak District National Park, Derbyshire, UK. September.

Alex Hyde / A millstone grit formation known as the 'Salt Cellar' on Derwent Edge, with Common Heather (Calluna vulgaris) in bloom, Peak District National Park, Derbyshire, UK. September.

LYNN M. STONE / Reddish Egret (Egretta rufescens) standing in salt water bay; common red morph in breeding plumage; Tampa Bay, Florida, USA

Pete Oxford / Brown Pelican beak (Pelecanus occidentalis urinator) Hyper saline solution dripping from the beak tip. This is a common phenomenon amongst sea birds which have a salt gland capable of removing excess...

Robin Chittenden / English springer spaniel putting up and chasing a Common redshank (Tringa totanus) on salt marshes, Morston, Norfolk, UK.

Tony Heald / Three Common zebra {Zebra burchelli} on the Etosha pan, Etosha NP, Namibia