Ashley Cooper / Dairy cow with a full udder

Jeff Foott / Maasai man shooting arrow to open jugular vein on cow for blood drinking ceremony. Maasai Mara, Kenya September 2006.

David Kjaer / Blood-vein moth (Timandra comae) Wiltshire, England, UK, June.

Rod Williams / Small Blood-Vein moth (Scopula imitaria) resting on a wall at night Brockley, Lewisham, London, UK July

Lorraine Bennery / Caterpillar Blood-vein moth (Timandra griseata), Isere, France, April.

David Kjaer / Blood-vein (Timandra comae) Wiltshire, UK

Eric Baccega / Cattle herders of the Suri / Surma tribe draining blood from the jugular vein of a cow to drink. Omo river Valley, Ethiopia, September 2014.

Eric Baccega / Cattle herder of the Suri / Surma tribe using bow and arrow to drain blood from the jugular vein of a cow to drink. Omo river Valley, Ethiopia, September 2014.

Eric Baccega / Cattle herder of the Suri / Surma tribe draining blood from the jugular vein of a cow to drink. Omo river Valley, Ethiopia, September 2014.

Jussi Murtosaari / Blood-vein moth on leaf (Timandra comae) South Karelia, southern Finland, June.

Christian Ziegler / Leaf-nosed Bat (Phyllostomidae) flight muscles and blood vessels in the wing membrane, Smithsonian Tropical Research Station, Barro Colorado Island, Panama

Christian Ziegler / Leaf-nosed Bat (Phyllostomidae) wing showing veins, Smithsonian Tropical Research Station, Barro Colorado Island, Panama