Doug Gimesy / Grey-headed flying-fox (Pteropus poliocephalus) defacating by hanging from thumbs the 'right way up', Yarra Bend Park, Victoria, Australia, April.

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 / Little grebe (Tachybaptus ruficollis) chasing a small fish jumping out of the water, before finally catching then eating it, Western Thailand.

Neil Challis / Two juvenile Long-tailed macaques (Macaca fascicularis) play fighting in a tree during a shower, Western Thailand.

Neil Challis / Asian water monitor (Varanus salvator) swimming through lake, early morning, Western Thailand.

Neil Challis / Asian water monitor (Varanus salvator) emerging from water, then crossing land, before swimming away, Western Thailand.

David Weiller / Aerial tracking shot of locals feeding a juvenile Whale shark (Rhincodon typus) and swimming past a crowd of tourists, Oslob, Philippines, May.

David Weiller / Aerial tracking shot of locals feeding a juvenile Whale shark (Rhincodon typus) and swimming past a crowd of tourists, Oslob, Philippines, May.

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.

Marie Read / Common loon (Gavia immer) adult swimming with a chick resting on its back, Presque Isle County, Michigan, USA, June.

Marie Read / American bittern (Botaurus lentiginosus) calling / booming in a cattail marsh to mark territory, Salt Alkaline Lake, Kidder County, North Dakota, USA, June.

John Waters / Golden plover (Pluvialis apricaria) flock taking off and flying over saltmarsh, Steart Marshes WWT Reserve, Somerset, UK, November.

Lukas Schaefer / Rock ptarmigan (Lagopus muta) close up preening, Val Venosta, Italy, October.

Lukas Schaefer / Alpine ibex (Capra ibex) male walking up a mountain in the snow, Gran Paradiso, Italy, December.

Vishal Jadhav / Exhausted Short-eared owl (Asio flammeus) surrounded by House crow (Corvus splendens) group at dawn, one crow dives down to attack, Maharashtra, India, April.

Vishal Jadhav / Short-eared owl (Asio flammeus) stood surrounded by a group of House crows (Corvus splendens) trying to find weakness by snapping at its feathers, Maharashtra, India, April.

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.

Joel Sartore / Photo Ark / Snow leopard (Panthera uncia) looking up, Miller Park Zoo. Vulnerable. Captive.

Joel Sartore / Photo Ark / Red-crested turaco (Tauraco erythrolophus) looking around and raising crest, Tracy Aviary. Captive.

Joel Sartore / Photo Ark / Himalayan monal pheasant (Lophophorus impejanus) male looking around, Pheasant Heaven. Captive.

Joel Sartore / Photo Ark / Madagascan fish eagle (Haliaeetus vociferoides) flaring its head feathers, Madagascar's Tsimbazaza Botanical and Zoological Park. Captive.

Joel Sartore / Photo Ark / Painted stork (Mycteria leucocephala) snapping towards the camera, Tracy Aviary. Captive.

Joel Sartore / Photo Ark / Two African crowned cranes (Balearica regulorum regulorum) looking around, then one ruffles its feathers, Lincoln Children's Zoo. Captive.

Joel Sartore / Photo Ark / Great green macaw (Ara ambiguus) turning its head and moving tongue, Tracy Aviary. Captive.

Vishal Jadhav / Asian green bee-eater (Merops orientalis) hunting insects from perch in the grass, Maharashtra, India, July.

Vishal Jadhav / Indian jackal (Canis aureus indicus) pair howling, Maharashtra, India, September.

Vishal Jadhav / Indian jackal (Canis aureus indicus) female grooming male's head, Maharashtra, India, September.

Doug Gimesy / Grey-headed flying-fox (Pteropus poliocephalus) feeding on pink Eucalyptus blossom, Olinda, Australia, February. Rescued animal in controlled conditions.

Doug Gimesy / Grey-headed flying-fox (Pteropus poliocephalus) feeding on red Eucalyptus blossom, Olinda, Australia, February. Rescued animal in controlled conditions.

Noemie Stroh / Orbicular batfish (Platax orbicularis) schooling into the blue, Shark Reef, Ras Mohamed National park, Red Sea, Egypt, June.

Noemie Stroh / Napoleon wrasse (Cheilinus undulatus) female swimming through soft coral garden, Daedalus, Red Sea, Egypt, August.

Noemie Stroh / Hawksbill turtle (Eretmochelys imbricata) female swimming above stony coral reef, Elphinstone, Red Sea, Egypt, August.

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.

Lewis Jefferies / Red squirrel (Sciurus vulgaris) feeding on the ground in the Cairngorms National Park, Scotland, UK, June.

Matt Roseveare / White-throated dipper (Cinclus cinclus) de-shelling caddisfly larva (Trichoptera) then eating it, River Kennal, Cornwall, UK, February.

Matt Roseveare / Parson's chameleon (Calumma parsonii) catching insect with tongue, Eastern rainforests of Madagascar, September.