Jabruson / Hippopotamuses fighting (Hippopotamus amphibius) taken before major crash in numbers in the 1990s due to political instability and hunting. Rwindi sector of the Virunga National Park. Democratic Repub...

Claudio Contreras / Mexican / Brown Vine Snake (Oxybelis aeneus) with mouth open. Maria Madre Island, Islas Marias Biosphere Reserve, Sea of Cortez (Gulf of California), Mexico, June.

Mike Wilkes / Starling feeding chick at nest (Sturnus vulgaris) Worcs, UK

Jabruson / Hippopotamus (Hippopotamus amphibius) low-angle view into the gaping mouth of a yawn, Rwindi sector of the Virunga National Park. This was prior to the decimation of the hippo population numbers at th...

Edwin Giesbers / Tufted Duck (Aythya fuligula) male on water with open gape showing serrations to the beak. The Netherlands, June.

Mark Taylor / Baby Blackbird (Turdus merula) portrait, with wing feathers in pin, and gape flange visible, sitting in profile.

Miles Barton / Shingleback / Sleepy lizard (Trachydosaurus / Tiliqua rugosus) adult gape display to deter predator, Burra, South Australia

WILLIAM OSBORN / Barn swallow fledglings {Hirundo rustica} gape at the prospect of food, Gloucestershire, England, UK

Jose B. Ruiz / Rufous scrub robin (Rufous warbler) chicks (Erythropygia galactotes) in nest. Spain, Europe

Juan Manuel Borrero / European eel {Anguilla anguilla} Delta del Ebro NP, Catalonia, Spain.

Niall Benvie / Common buzzard (Buteo buteo) calling. Scotland, Europe

Pal Hermansen / Robin (Erithacus rubecula) chick begging for food by exposing bright yellow gape, Akershus, Norway.