Mike Read / Magellanic penguin (Spheniscus magellanicus) calling, Falkland Islands

Edwin Giesbers / Konik Wild Horse (Equus ferus caballus) yawning. The Netherlands, November.

Gerrit Vyn / Adult Red-necked Grebes (Podiceps grisegena) in breeding plumage performing "whinny-braying" duet in defense of territory. Fairbanks, Alaska, USA, July.

Richard Du Toit / Burchell's Zebra (Equus burchellii) close-up of face of braying animal, Hluhluwe-umfolozi Game Reserve, South Africa

Anup Shah / Common zebra foal braying {Equus quagga} Masai Mara GR, Kenya East Africa

Anup Shah / Common zebra braying {Equus quagga} Masai Mara GR, Kenya East Africa

Richard Du Toit / Zebra (Equus quagga) male braying, with scars from fights, Rietvlei Nature Reserve, Gauteng Province, South Africa, October.

Richard Du Toit / Burchell's Zebra (Equus burchellii) braying, Rietvlei Nature Reserve, South Africa

Ann & Steve Toon / Cape mountain zebra (Equus zebra zebra) braying, Mountain Zebra National Park, Eastern Cape, South Africa, February

Heike Odermatt / Magellanic Penguin (Spheniscus magellanicus) calling at its burrow, Sea Lion Island, Falkland Islands

Richard Du Toit / Burchell's Zebra (Equus burchellii) pair interacting, Rietvlei Nature Reserve, Gauteng, South Africa

Konrad Wothe / Camargue horse (Equus caballus) yawning, Camargue, France, April