Mark Taylor / Roborovski Hamster (Phodopus roborovskii) asleep sitting up, against white background

Stefan Christmann / Emperor penguin (Aptenodytes forsteri) male brooding snoozing young chick. Atka Bay, Antarctica. August.

Sven Zacek / Ural owl (Strix uralensis) female snoozing on nest at dusk. Tartumaa, Southern Estonia. March.

Michael Pitts / Hawaiian Monk seal (Monachus schauinslandi) sleeping on the deck of a wrecked barge. Midway atoll. Central Pacific.

Mark Taylor / Cute tabby kitten, Fosset, 5 weeks, sleeping in a Father Christmas hat, against white background

Mark Taylor / Munsterlander, Helena, 5 months, lying asleep with her chin on the floor, against white background

Jeff Vanuga / Greater Flamingos (Phoenicopterus roseus) sleeping at the Parc Ornithologique Pont De Gau, Les Saintes Maries de la Mer, Camargue, France, May.

Jeff Vanuga / Greater Flamingos (Phoenicopterus roseus) sleeping at the Parc Ornithologique Pont De Gau, Les Saintes Maries de la Mer, Camargue, France, May.

Will Burrard-Lucas / Meerkat (Suricata suricatta) babies asleep, Makgadikgadi Pans, Botswana.

Ernie Janes / *** Starlings (Sturnus vulgaris) on power lines at sunset, UK, October.

Michael Durham / Western small-footed bat (Myotis ciliolabrum) roosting on rock at night, near Sulphur Springs, Washington, USA, June.

Michael Durham / Western small-footed bat (Myotis ciliolabrum) roosting on a rock at night, near Sulphur Springs, High desert, Washington, USA, June.