Cyril Ruoso / Bonobo (Pan paniscus) mother resting with her newborn baby, Lola Ya Bonobo Sanctuary, Republic of the Congo. Non-ex

Theo Webb / Female Bonobo (Pan paniscus) resting with her infant, Max Planck research site, LuiKotale, Salonga National Park, Democratic Republic of Congo.

Anup Shah / Eastern chimpanzee (Pan troglodytes schweinfurtheii) male 'Faustino' aged 22 years resting on a fallen branch. Gombe National Park, Tanzania.

Philippe Clement / Close up of a European river otter (Lutra lutra) lying on its back grooming its fur, Bayerischer Wald / Bavarian Forest National Park, Germany, October. Captive.

Philippe Clement / Close up of a European river otter (Lutra lutra) lying on its back, Bayerischer Wald / Bavarian Forest National Park, Germany, October. Captive.

Loic Poidevin / Juvenile Grizzly bear (Ursus arctos horribilis) lying on a bed of moss, Khutzeymateen Grizzly Bear Sanctuary, British Columbia, Canada, June.

Gerry Ellis / Sea Otter (Enhydra lutris) adult reclining on its back at water's surface eating north Pacific Coast, North America

Patricio Robles Gil / Sambar (Cervus unicolor) female resting with three Common Mynas (Acridotheres tristis) perching on head and back, Ranthambore National Park, India

Jabruson / Bonobo (Pan paniscus) male sitting on a branch and pulling a bunch of fruit off a Dialium tree (Dialium sp), he then lays on his back and begins to eat the fruit, Lomako Yokokala Faunal Reserve, Provi...