Terry Whittaker / 2020VISION / Water Vole (Arvicola amphibius / terrestris) foraging by water. Kent, UK, August. Did you know? Although mostly vegetarians, some water voles have been known to eat frogs' legs to get extra protein.

Tim Laman / Large school of Trevally (Caranx) shelter beneath the jetty at Arborek Village. Many village docks in this area act as shelter for these fish, which provide a handy source of protein for villagers in...

Jabruson / Sun-dried fish provides many families with a readily available supply of protein and a product to sell at local markets, Gamba, Gabon

SINCLAIR STAMMERS / Cyanobacterium / Blue green algae (Spirulina platensis) which is used as a health food because of its high protein content. Nomarski photomicrograph

Simon Colmer / Lacewing (Chrysopidae) eggs hanging from tulip petals on protein stalks,

Piotr Naskrecki / Unidentified Cockroach on right, eating old cuticle on left after molting, recovering protein and carbohydrates shed during molting, Costa Rica

Luiz Claudio Marigo / Caboclo family with their bull, alternative source of protein, Amazonia, Brazil

Philippe Clement / Chacma baboon baby baboon killed by dominant male for protein Kruger NP S Africa

Colin Monteath / Antarctic fish on ice, their blood contains glyco-protein that acts as anti-freeze, Port Lockroy, Antarctica