Ingo Arndt / Northern elephant seal {Mirounga angustirostris} male sleeping, California

LYNN M. STONE / Sleeping mixed-breed piglet in straw, Maple Park, Illinois, USA

Nick Upton / Flesh fly (Sarcophaga sp.) "bubbling" regurgitated stomach contents in order to increase the concentration of its food by evaporating excessive water content. Wiltshire, UK, September.

Nick Upton / Flesh fly (Sarcophaga sp.) "bubbling" regurgitated stomach contents in order to increase the concentration of its food by evaporating excessive water content. Wiltshire, UK, September.

Katherine Feng / Giant Panda (Ailuropoda melanoleuca), Xiang Xiang the first captive raised panda to be released into the wild, in pre release enclosure eating bamboo, Wolong Nature Reserve, endangered, China

Flip Nicklin / Bearded Seal (Erignathus barbatus) male resting on ice floe with head dyed red from the high iron content of ocean mud in which he hunts for shrimp and clams, Svalbard, arctic Norway

Jabruson / Western lowland gorilla male silverback "Faust" eating soil for mineral content in bai (forest clearing) Odzala NP, Democratic Republic of Congo. Died July 2004, probably due to Ebola virus.

Jabruson / Western lowland gorilla silverback male eating soil for mineral content, Odzala NP, Democratic Republic of Congo.

Jabruson / Male Western lowland gorilla silverback eating soil for mineral content in Bai (rainforest clearing) Odzala NP, Democratic Republic of Congo, Lokoue Bai white silverback.

Jabruson / Silverback Western lowland gorilla eats soil for mineral content {Gorilla gorilla gorilla} Odzala NP, Democratic Republic of Congo.

Heather Angel / Rock jasmine (Androsace sericea) flowers. Colour of corona ring indicates age and nectar content of flower. Mountains of Heaven / Tian Shan, Kazakhstan. June.

John Shaw / Circular salt patterns form around Arrowweed (Pluchea sericea) noting different moisture content levels in the soil. The Devil's Cornfield area, Death Valley National Park, California, USA. Januar...