Burrowing owl (Athene cunicularia) pair, Salton Sea, California, United States of America, North America

A pair of adult variegated lizardfish (Synodus variegatus), off Bangka Island, near Manado, Sulawesi, Indonesia, Southeast Asia, Asia

Two Sandhill Cranes (Grus canadensis) in flight in late afternoon light, Bosque Del Apache National Wildlife Refuge, New Mexico, United States of America, North America

Adult kelp goose pair (Chloephaga hybrida), female in front, New Island Nature Reserve, Falkland Islands, South America

A lion pair (Panthera leo) on a kopje known as Lion Rock in Lualenyi reserve, Tsavo, Kenya, East Africa, Africa

Mounts Lavarella and Conturines behind a pair of snow covered wooden barns at the Alta Badia ski resort near Corvara, Dolomites, South Tyrol, Italy, Europe

Arctic tern (Sterna paradisaea) with chick. Farne Islands, off Northumberland coast, UK

A pair of American oystercatchers (Haematopus palliatus), hunting along the shore, Isla Rasa, Baja California, Mexico, North America

Caliph's palace, Samarra, Iraq, Middle East

Cape gannet (Morus capensis) pair, Lamberts Bay, South Africa, Africa

A pair of juvenile male southern elephant seals (Mirounga leonina), mock-fighting in Karukinka Natural Park, Chile, South America

Reticulated Giraffe (Giraffa camelopardalis reticulata), Samburu National Park, Kenya, East Africa, Africa

Trumpeter swan (Cygnus buccinator) pair, Potter Marsh, Alaska, United States of America, North America

Gannet (Morus bassanus) flying. Bass Rock, Scotland

Ringed plovers (Charadrius hiaticula), Scotland, United Kingdom, Europe

A pair of little bee-eaters (Merops pusillus), perched in Chobe National Park, Botswana, Africa

A pair of hoodoo formations near the Red Basin in Petrified Forest National Park Arizona called the Red Basin Gnomes.

Western grebe (Aechmophorus occidentalis) courtship, Bear River Migratory Bird Refuge, Utah, United States of America

A pair of bat-eared foxes (Otocyon megalotis), Serengeti National Park, Tanzania, East Africa, Africa

Shags on nests (Phalacrocorax aristotelis). Farne Islands, Northumberland, UK

California sea lion (Zalophus californianus) pair hauled out on Isla San Pedro Martir, Baja California, Mexico, North America

Secretarybird (Sagittarius serpentarius) pair upon their nest, Masai Mara National Reserve, Kenya, East Africa, Africa

A pair of juvenile male southern elephant seals (Mirounga leonina), mock-fighting in Karukinka Natural Park, Chile, South America

A pair of juvenile brown tangs (Zebrasoma scopas), on the reef off Kawe Island, Raja Ampat, Indonesia, Southeast Asia, Asia

Place St. Sulpice, Paris, France, Europe

Pair of Glaucous gulls standing on iceberg, Nunavut and Northwest Territories, Canada, North America

Open Torah, tallit and pair of glasses, France, Europe

Azure damselfly (Coenagrion puella) pair mating and casting shadow on a leaf, Wiltshire, England, United Kingdom, Europe

Close up of pair of giraffe (Giraffa), South Luangwa National Park, Zambia, Africa

A pair of juvenile male southern elephant seals (Mirounga leonina), mock-fighting in Karukinka Natural Park, Chile, South America

Pygmy falcon pair (Polihierax semitorquatus), Kgalagadi Transfrontier Park, Northern Cape, South Africa, Africa

Lion pair (Panthera leo), Masai Mara National Reserve, Kenya, East Africa, Africa

Family of Indian tigers (Bengal tiger) (Panthera tigris tigris), Bandhavgarh National Park, Madhya Pradesh state, India, Asia

Pair of butterfly fish (Chaetodon Senilarvatus), Red Sea, Sudan, Africa

Pair of customised Jeepney trucks, the ubiquitous national transport, Bacolod City, Philippines, Southeast Asia, Asia

Horse-drawn gypsy caravan, Dingle Peninsula, County Kerry, Munster, Eire (Ireland), Europe

Traditional Turkman wedding, Ashkabad, Turkmenistan, Central Asia, Asia

Couple dressed in masks and costumes taking part in Carnival, Venice Carnival, Venice, Veneto, Italy, Europe

Couple looking out to bamboo forest from tea ceremony room, Kamakura city, Kanagawa prefecture, Honshu island, Japan, Asia

Maiden and lad standing on chairs held by other lads to cheer their union, in traditional dress, St. Martin Feast with Wreath Festival, Svatoborice-Mistrin, Brnensko, Czech Republic, Europe

Chosen couple in traditional dress, dancing, St. Martin Feast with Wreath Festival, Svatoborice-Mistrin, Brnensko, Czech Republic, Europe

Couple snorkelling, Chapera island (Contadora), Las Perlas archipelago, Panama, Central America

Couple on bridge, Aruba, West Indies, Dutch Caribbean, Central America

Couple on bridge, Aruba, West Indies, Dutch Caribbean, Central America

Couple on bridge at sunset, Aruba, West Indies, Dutch Caribbean, Central America

Ebony wood and ivory inlay detail on one of the pair of throne chairs, Sirohi Palace, Sirohi, Southern Rajasthan state, India, Asia

Two walkers with rucksacks on the Cotswold Way footpath, Stanway village, The Cotswolds, Gloucestershire, England, United Kingdom, Europe

Hikers on hiking track, Vrsic Pass, Soca Valley, Triglav National Park, Julian Alps, Slovenia, Europe

Slapton Sands, Slapton Ley, South Hams, Devon, England, United Kingdom, Europe

Man and woman canoeing in Mirror Lake, Chugach Mountains, Anchorage, Alaska, United States of America, North America

Track from Smuksjoseter toward Formokampen, Rondane National Park, Norway, Scandinavia, Europe

Local man, Damascus, Syria, Middle East

Pair of horses decorated with colourful headgear, Feria de Abril (April Fair), Seville, Andalucia (Andalusia), Spain, Europe

Pair of beach shoes on washing line

Farmer using pair of oxen to turn water wheel to draw water from well for irrigation at Samad in Pali District of Rajasthan, Western India

Snowmobiling in the arctic alps in the Arctic Circle near Holt in the region of Tromso, Northern Norway

Bull with cow in meadow in County Clare, West of Ireland

Farmer using pair of oxen to plough field for lentil crop in fields at Nimaj, Rajasthan, Northern India

Farmer using pair of oxen to plough field for lentil crop in fields at Nimaj, Rajasthan, Northern India

Male mallard drake and female duck pair sleeping in meadow, The Cotswolds, Oxfordshire, UK

Alaskan Huskies harnessed for dog-sledding at Villmarkssenter wilderness centre, Kvaloya Island, Tromso in Arctic Circle Northern Norway

Male cock pheasant, Phasianus colchicus, and female hen pheasant in meadow in The Cotswolds, Oxfordshire, UK

Alaskan Huskies dog-sledding at Villmarkssenter wilderness centre on Kvaloya Island, Tromso in Arctic Circle Northern Norway

Pair of Jackdaws, Corvus monedula, nesting in a turret in Parce-Sur-Sarthe, France

Alaskan Huskies dog-sledding at Villmarkssenter wilderness centre on Kvaloya Island, Tromso in Arctic Circle, Northern Norway

Farmer using pair of oxen to turn water wheel to draw water from well for irrigation in Pali District of Rajasthan, Western India

Pair of adult llamas, one male one female, at Ferme de l'Eglise, Normandy, France

Pair of adult llamas, one male one female, at Ferme de l'Eglise, Normandy, France

Alaskan Huskies dog-sledding at Villmarkssenter wilderness centre on Kvaloya Island, Tromso in Arctic Circle, Northern Norway

Pair of Weavers birds on tree branch at Chattra Sagar nature reserve at Nimaj, Rajasthan, Northern India

Alaskan Huskies dog-sledding at Villmarkssenter wilderness centre on Kvaloya Island, Tromso in Arctic Circle Northern Norway

Alaskan Huskies dog-sledding at Villmarkssenter wilderness centre on Kvaloya Island, Tromso in Arctic Circle, Northern Norway

Alaskan Huskies dog-sledding at Villmarkssenter wilderness centre on Kvaloya Island, Tromso in Arctic Circle Northern Norway

Alaskan Huskies dog-sledding at Villmarkssenter wilderness centre on Kvaloya Island, Tromso in Arctic Circle, Northern Norway

Alaskan Huskies harnessed for dog-sledding at Villmarkssenter wilderness centre Kvaloya Island, Tromso, Arctic Circle Northern Norway

Alaskan Huskies eagerly wait at Villmarkssenter wilderness adventure centre on Kvaloya Island, Tromso in Arctic Circle Northern Norway

Alaskan Huskies dog-sledding at Villmarkssenter wilderness centre on Kvaloya Island, Tromso in Arctic Circle Northern Norway

Farmer using pair of oxen to turn water wheel to draw water from well for irrigation in Pali District of Rajasthan, Western India

Alaskan Huskies dog-sledding at Villmarkssenter wilderness centre on Kvaloya Island, Tromso in Arctic Circle, Northern Norway

Swans on River Coln by Arlington Row cottages traditional almshouses in Bibury, Gloucestershire, The Cotswolds, UK

Brown Herefordshire bull and fresian cow in mating process in meadow in Gloucestershire

Blue-footed Booby bird on the Galapagos Islands, Ecuador with a pair of young birds

A pair of Johnny Rook or Striated Caracara (Phalcoboenus australis) birds, one of the world's rarest birds of prey, resting on the beach of Sea Lion Island in the Falklands, South Atlantic. Behind are elephant seals.

Water sellers in brightly coloured costumes in the Djemma El Fna square in Marrakesh, Morocco

Pair of Yellow Spot Signet Turtles on log in Lake Sandoval, Peruvian Rainforest, South America

A pair of Upland Geese on Sea Lion Island in the Falkland Islands, South Atlantic (The female goose has a ruddy heads, the male has a white head).

Pair of Steamer ducks, Sea Lion Island, Falkland Islands

Pair of Elephant seals one showing scars of fighting on neck, Sea Lion Island, Falkland Islands

A pair of turtles on the beach in Cyprus

Traditional marriage, Place du Kraton, Jogyakarta, island of Java, Indonesia, Southeast Asia, Asia

Blesbok (Damaliscus dorcas), Kariega Game Reserve, South Africa, Africa

Woman out for a stroll with a pair of terrier dogs along a country lane on a rainy day at Swinbrook, The Cotswolds, Oxfordshire, England, United Kingdom, Europe

King penguin (Aptenodytes patagonica) pair pre-mating behaviour, Salisbury Plain, South Georgia, Polar Regions

Hiking near the Matterhorn, Swiss Alps, Switzerland, Europe

Two Budgerigars (common pet parakeet) (shell parakeet) (Melopsittacus undulatus) in captivity, Rio Grande Zoo, Albuquerque Biological Park, Albuquerque, New Mexico, United States of America, North America

Couple on a jet-ski, Contadora island, Las Perlas archipelago, Panama, Central America

Pygmy man posing with his wife and hunting spear, southeast area, Cameroon, Africa

Contadora island, Las Perlas archipelago, Panama, Central America

Graylag geese, Anser anser, on Tarn Hows lake, in the Lake District National Park, Cumbria, UK

Brown Herefordshire bull and fresian cow in meadow in Gloucestershire