North American timber wolf (Canis Lupus) howling in the snow in forest, Wolf Science Centre, Ernstbrunn, Austria, Europe

North American Timber wolf, Canis Lupus howling in the snow in deciduous forest.

North American timber wolf (Canis Lupus) howling in the snow in deciduous forest, Wolf Science Centre, Ernstbrunn, Austria, Europe

Female trumpeter hornbill (Bycanistes bucinator) calling, Hluhluwe Game Reserve, South Africa, Africa

Red deer stag (Cervus elaphus) roaring, Arran, Scotland, United Kingdom, Europe

Elephant seals, Moltke Harbour, Royal Bay, South Georgia, South Atlantic

Adult bull southern elephant seal (Mirounga leonina) issuing a bellowing challenge at Gold Harbour on South Georgia, Polar Regions

Californian ground squirrel. Spermophilus beecheyi. Calling at entrance to burrow. Monterey bay, usa

Close-up of female cheetah (Acinonyx jubatus) yawning at camera, Serengeti, Tanzania

Pileated Woodpecker

Close up of lion growling

Lion cub walking on log

Lion roaring

Hippopotamus yawning

Hippopotami swimming in lake