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}

Doug Perrine / Humpback whale mother and calf {Megaptera novaeangliae} Hawaii, USA Pacific Ocean - taken under research permit #633 (Non-ex).

Anup Shah / Impala mother and baby, head to head {Aepyceros melampus} Masai Mara, Kenya

Anup Shah / Leopard cub playing with mother {Panthera pardus} Masai Mara, Kenya

Anup Shah / Young African elephant calf beside mother's trunk {Loxodonta africana} Masai Mara, Kenya