SCOTLAND: The Big Picture / Orca whales (Orcinus orca) pod surfacing together, Shetland, Scotland, UK. April.

SCOTLAND: The Big Picture / Orca (Orcinus orca) surfacing and blowing, Shetland, Scotland, UK, August.

Will Burrard-Lucas / Black and white image of African elephant (Loxodonta africana) bulls males facing off against each other, Tsavo Conservation Area, Kenya. Editorial use only.

Tui De Roy / Galapagos sea lion (Zalophus wollebaeki) killing tuna. A group of the sea lion bulls have learnt to herd Pelagic yellowfin tuna into a small cove, trapping them. The fish often leap ashore in an effor...

Tui De Roy / Galapagos sea lion (Zalophus wollebaeki) hunting tuna. A group of the sea lion bulls have learnt to herd Pelagic yellowfin tuna into a small cove, trapping them. The fish often leap ashore in an effor...

Tui De Roy / Galapagos sea lion (Zalophus wollebaeki) hunting tuna. A group of the sea lion bulls have learnt to herd Pelagic yellowfin tuna into a small cove, trapping them. The fish often leap ashore in an effor...

Sebastian Kennerknecht / African Elephant (Loxodonta africana) bulls fighting, Kruger National Park, South Africa

Mark Raycroft / Elk (Cervus elaphus) bulls fighting, North America

Donald M. Jones / Elk (Cervus elaphus) bulls fighting, western Canada

Wim van den Heever / African elephant (Loxodonta africana) three big bull elephants spending the late afternoon at waterhole, Ol'Donyo Kenya.

Neil Aldridge / Sable antelope (Hippotragus niger) bull charging through the shallows of the Selinda Spillway, with another behind, northern Botswana, August.

Danny Green / Moose Bull (Alces alces) walking in forest clearing, Denali National Park, USA, September