Donald M. Jones / Black-tailed Prairie Dog (Cynomys ludovicianus) pair greeting, South Dakota

Ashley Cooper / Sun rays reflected onto solar tower at Ivanpah Solar Thermal Power Plant, the largest solar thermal plant in the world. It covers 4,000 acres of desert and produce 392 megawatts (MW) of electricity....

Tui De Roy / Volcan Alcedo Giant Tortoise (Chelonoidis nigra vandenburghi) pair in volcanic landscape, Alcedo Volcano, Isabela Island, Galapagos Islands, Ecuador

Tui De Roy / Blue-footed Booby (Sula nebouxii) males courting female, Punta Vicente Roca, Isabela Island, Galapagos Islands, Ecuador

Ingo Arndt / Baya weaver (Ploceus philippinus) subadult birds practising building 'play nest', Singapore.

Richard Du Toit / Burchell's Zebra (Equus burchellii) pair nuzzling, Rietvlei Nature Reserve, South Africa

Ben Hall / Galapagos sea lion (Zalophus wollebaeki) mother and young touching noses, Galapagos Islands, May

Chris & Monique Fallows / Wandering albatross (Diomedea exulans), engaged in mating display. South Georgia Island, Southern Ocean.

Michael D. Kern / Two Dyeing dart frogs (Dendrobates tinctorius) against background, captive occurs in Guyana, Suriname, Brazil, and French Guiana. Available for on-line use only.

Fiona Rogers / Tana mangabey (Cercocebus galeritus) female grooming a juvenile. Tana River Forest, South eastern Kenya.

Nick Garbutt / Scarlet Ibis (Eudocimus ruber) flying into roost sight at dusk, Hato La Aurora Reserve, Los Llanos, Colombia, South America.

Nick Garbutt / Zebu Cattle (Bos primigenius indicus), Los Llanos, Colombia, South America.