Jan Wegener / Common Nighthawk (Chordeiles minor) male in display flight, Winnie, Texas
Matthew Maran / Red fox dog (Vulpes vulpes) jumping into an urban litter bin beside a busy road to feed, London, England, UK, August.
Doug Allan / Polar bear (Ursus maritimus) male well fed, jumping over a crack in the melting pack ice before sniffing and tasting the air, Svalbard, July, 2015.
Vishal Jadhav / Great hornbill (Buceros bicornis) male flying in and landing on nest hole with a Barbet chick kill to feed his young, Maharashtra, India, May.
Vishal Jadhav / Great hornbill (Buceros bicornis) male feeding its young with a Barbet chick, Maharashtra, India, May.
Laurie Hedges / Bison (Bison bison) bull kicking up dust, urinating and then rolling on the ground for scent, Montana, USA, August.
Laurie Hedges / Elk (Cervus canadensis) trapped in fencing, trying to pull its antlers out of the wire, Montana, USA, August.
Neil Challis / Male Baya weaver (Ploceus philippinus) working on hanging nest, Central Thailand, August.
Neil Challis / Long-tailed macaque (Macaca fascicularis) male and small puppy facing up to each other, Central Thailand, July.
Neil Challis / Close up of Long-tailed macaque (Macaca fascicularis) male sleeping in a tree, Central Thailand, June.
Vishal Jadhav / Great hornbill (Buceros bicornis) male feeding the female fig fruits as she sits on the nest inside tree trunk, before jumping around the nest hole, Maharashtra, India, April.
Vishal Jadhav / Great hornbill (Buceros bicornis) male feeding the female fig fruits as she sits on the nest inside tree trunk, Maharashtra, India, April.
Tony Wu / Two Siberian flying squirrel (Pteromys volans orii), just emerged from nest, taking moment prior to foraging. Hokkaido, Japan. February.
Doug Gimesy / Grey-headed flying-fox (Pteropus poliocephalus) aggressive mating behaviour (wrestling, biting) male eventually moves away, Yarra Bend Park, Victoria, Australia, April.
Doug Gimesy / Grey-headed flying-fox (Pteropus poliocephalus) male involved in courtship / mating behaviour including licking female's genitalia; male grooming his own penis, bickering and female climbing away, Yar...
Neil Challis / Giant golden orb weaver spider (Nephila pilipes) focus pull from a small male to much larger female in the background, Western Thailand.
Marie Read / Ruby-throated hummingbird (Archilochus colubris) male flies in to feed on nectar from Eastern red columbine flower (Aquilegia canadensis), Freeville, New York, USA, June.
Marie Read / Eastern bluebird (Sialia sialis) male feeding on Winterberries (Ilex verticillata) before flying off, Freeville, New York, USA, January.
Lukas Schaefer / Alpine ibex (Capra ibex) male walking up a mountain in the snow, Gran Paradiso, Italy, December.
Staffan Widstrand / Pair of Eurasian bee-eaters (Merops apiaster) perched on branch, Pusztaszer reserve, Hungary. May.
Joel Sartore / Photo Ark / Masked flying fox (Pteropus personatus) male hanging upside down with wings open, private collection, Indonesia. Captive.
Joel Sartore / Photo Ark / Gray woolly monkey (Lagothrix cana) male picking up and holding its tail, Mantenedor da Fauna Silvestre Cariua. Endangered. Captive.
Vishal Jadhav / Red-breasted flycatcher (Ficedula parva) male hunting flying insects from a rock, Maharashtra, India, February.
Vishal Jadhav / Great hornbill (Buceros bicornis) pair performing courtship feeding ritual, passing berry from beak to beak, then female eats berry, Maharashtra, India, February.
Charlie Hamilton-James / Male Lion (Panthera leo) resting on the savannah at dawn, Naboisho Conservancy, Masai Mara, Kenya.
Joel Sartore / Photo Ark / Himalayan monal pheasant (Lophophorus impejanus) male looking around, Pheasant Heaven. Captive.
Vishal Jadhav / Indian jackal (Canis aureus indicus) female grooming male's head, Maharashtra, India, September.
Noemie Stroh / Green turtles (Chelonia mydas) mating on coral reef, Rocky Island, Red Sea, Egypt, June.
Vishal Jadhav / Spotted owlet (Athene brama) female looking out of nest in rocks, males appears then flies off, Maharashtra, India, January.
Oscar Dewhurst / Mandarin duck (Aix galericulata) drake swimming on pond, backlit by rising sun and bokeh effect, Richmond Park, London, UK. February.
David Pattyn / Pair of Great crested grebes (Podiceps cristatus) performing courtship dance, The Netherlands, Europe. March.
David Pattyn / Pair of Great crested grebes (Podiceps cristatus) courtship dance display, The Netherlands, Europe. March.
Brian Bevan / Yellowhammer (Emberiza citronella) male singing from bramble then flies away, Bedfordshire, UK, June.
Brian Bevan / Common Kingfisher (Alcedo atthis) male dives then catches loach fish, Bedfordshire, UK, April.
Brian Bevan / Common Kingfisher (Alcedo atthis) male fishing from blackthorn branch, catches then eats fish, Bedfordshire, UK, April.
Brian Bevan / Great crested grebe (Podiceps cristatus) courtship weed dance, Bedfordshire, UK, April.
Eric Baccega / Male Chimpanzee (Pan troglodytes troglodytes) trying to catch fallen fruits using stick as a tool, Conkouati-Douli National Park, Republic of Congo, Africa.
Will Burrard-Lucas / Leopard (Panthera pardus) male on moonlit night, Laikipia, Kenya. Taken using camera trap with a long exposure time to expose the stars and a flash to expose the foreground, creating a ghostly effect....