Matthew Maran / Red fox (Vulpes vulpes) dog interacting with a vixen in an urban garden. North London, UK. June.

Matthew Maran / Red fox (Vulpes vulpes) dog interacting with a vixen in an urban garden. North London, UK. July.

Marie Read / Black-necked stilts (Himantopus mexicanus) pair performing post-copulatory display (as copulation ends, the male slides off the female leaving his wings draped over her and crossing his bill with hers...

Tony Wu / Four Sperm whales (Physeter macrocephalus) rubbing their heads together while socializing, forming an X shape pattern. Caribbean.

Tony Wu / Four Sperm whales (Physeter macrocephalus) rubbing their heads together while socializing, hanging down. Caribbean.

Neil Aldridge / African Lion (Panthera leo) cub reaches for a moment of intimacy with its father, Northern Tuli Game Reserve, Botswana

Aflo / ic-02802 Two domestic cats sleeping with heads close together {Felis catus}

Aflo / ic-02801 View of heads of two domestic cats sleeping close together {Felis catus}

Anup Shah / Olive baboon adult sniffing baby.

Anup Shah / Lionesses grooming each other Masai Mara, Kenya

TJ Rich / Female Red fox {Vulpes vulpes} with cub, intimate portrait of affection and close bond between mother and young, England, UK, Europe

Jen Guyton / Meerkat pup (Suricata suricatta) huddling close to its family members in the Kalahari Desert, South Africa.

Dave Watts / Colombian spider monkey (Ateles fusciceps rufiventris) group. Captive, Critically endangered species.

Carol Walker / Head portrait of black Andalusian stallion and mare meeting for the first time in southern Spain, Europe.

Aflo / Stray cats, white point cat grooming ginger and white patched tabby, Nagoya, Japan.

Aflo / Stray cats, white point cat grooming ginger and white patched tabby, Nagoya, Japan.

Aflo / Stray cats, white point cat and ginger and white patched tabby sleeping, Nagoya, Japan.

Denis-Huot / Lioness (Panthera leo)s from a pride, Masai-Mara Game Reserve, Kenya

Christophe Courteau / West African giraffe calves {Giraffa camelopardis peralta}. Sahel, Niger.

Christophe Courteau / African lion pride {Panthera leo} Mother & cubs. Okavango delta, Botswana. 2006 BEMROSE

Sergey Gorshkov / African lions (Panthera leo) close up and low angle shot of pride feeding on carcass, Okavango Delta, Botswana

Anup Shah / Spotted hyenas (Crocuta crocuta) greeting. Masai Mara National Reserve, Kenya. February

Edwin Giesbers / Hamadryas baboon (Papio hamadryas) male and female pair. Captive. Apenheul zoo; the Netherlands.

TJ Rich / Mountain gorilla {Gorilla berengei berengei} mother kissing hand of week-old baby, Parc des Volcans NP, Rwanda

Suzi Eszterhas / African Lion (Panthera leo), portrait of mother and cub (4 weeks) resting, Masai Mara Reserve, Kenya

Suzi Eszterhas / African Lion (Panthera leo) cub (4 weeks) playing with its mother whilst being groomed, Masai Mara Reserve, Kenya

Pete Oxford / Giraffes {Giraffa camelopardis} Hwange NP, Zimbabwe.

TJ Rich / Mother and cub Red fox {Vulpes vulpes}, young cub yawning, near den, England, UK, Europe

Richard Flack / Shelley's francolin (Scleroptila shelleyi) pair, preening, Kruger National Park, South Africa.

Bruce Thomson / Mareeba rock wallaby (Petrogale mareeba) joey peeping out of mother's pouch, Atherton Tablelands, Queensland, Australia.

Bruce Thomson / Female Mareeba rock wallaby (Petrogale mareeba) with joey in pouch, standing on granite boulders, Atherton Tablelands, Queensland, Australia.

Tui De Roy / Swallow-tailed gull (Creagrus furcatus), pair, Genovesa Island, Galapagos, South America.