Anup Shah / African Lion (Panthera leo) juvenile reaching out with curiosity, Masai Mara National Reserve, Kenya. March

Martin Dohrn / Group of lions (Panthera leo) at night, Masai Mara, Kenya. Photographed using 'Starlight Camera' technology without artificial lighting.

Andy Rouse / African lion (Panthera leo) mother and very young cub, Masai Mara, Kenya, Africa

John Downer / Male Lion walking {Panthera leo} Masai Mara Kenya. Image taken with Bouldercam remote

Klein & Hubert / African lioness (Panthera leo) with her cub in savanna, Kenya, Africa.

Hermann Brehm / Lion (Panthera leo), females interacting, with cub, Masai Mara, Kenya

Anup Shah / Lion (Panthera leo) males walking together . Masai Mara National Reserve, Kenya.

Tui De Roy / Galapagos sea lions (Zalophus wollebaeki) sub adult males playing with starfish, Mosquera Islet, Galapagos.

David Hall / Steller sea lions (Eumetopias jubatus), three playing underwater, Inian Island, Alaska, USA. August.

David Hall / Steller sea lions (Eumetopias jubatus) playing underwater, Inian Island, Alaska, USA. August.

Klein & Hubert / Lion (Panthera leo) male portrait, South Africa.

Klein & Hubert / Lion (Panthera leo) male portrait, South Africa.

Klein & Hubert / Lion (Panthera leo) male portrait, South Africa.

Tony Heald / African buffalo (Syncerus caffer) herd showing defensive behaviour as an African lioness (Panthera leo) walks by, Mana Pools National Park, Zimbabwe. September....

Tony Heald / Lion (Panthera leo) moving away from a defensive African buffalo (Syncerus caffer) Mana Pools National Park, Zimbabwe.

Philippe Clement / Leucistic white lions (Panthera leo krugeri) male and juveniles, Captive.

Nick Garbutt / Adult male lion (Panthera leo) standing on the banks of the Luangwa River, South Lunangwa NP. Zambia.

Ann & Steve Toon / RF - Lion (Panthera leo) head portrait at night, Zimanga private game reserve, KwaZulu-Natal, South Africa. (This image may be licensed either as rights managed or royalty free.)

Eric Baccega / Lion (Panthera leo) male walking. Masai Mara National Reserve, Kenya.

Felis Images / Asiatic lion (Panthera leo persica), female and cubs in morning light, cub biting mother's leg. Gir National Park, Gujarat, India. Photo?hillip Ross/Felis Images

Nick Hawkins / Steller's sea lions (Eumetopias jubatus) off the coast of the Great Bear Rainforest, near Bella Bella, British Columbia, Canada. August

Klein & Hubert / African lion (Panthera leo) portrait, South Africa

Andy Rouse / African Lion (Panthera leo) male at sunrise, Masai Mara, Kenya

Andy Rouse / African Lion (Panthera leo) cub age 2 months, Masai Mara, Kenya

Andy Rouse / African Lion (Panthera leo) cubs age 2 months playing, Masai Mara, Kenya

Denis-Huot / Lioness (Panthera leo) playing with litter, Masai-Mara Game Reserve, Kenya

Eric Baccega / Lioness (Panthera leo), aggressively rebuffing male lion banks of the Luangwa river, South Luangwa National Park, Zambia

Eric Baccega / Coalition of two African male lions (Panthera leo) resting on the banks of the Luangwa river, dry season, South Luangwa National Park, Zambia

Ann & Steve Toon / Lion (Panthera leo) male snarling at night, Zimanga private game reserve, KwaZulu-Natal, South Africa, September

Paul Williams / Lion (Panthera leo) close up of teeth while its snarling, captive.

Paul Williams / RF - Lion (Panthera leo) portrait, looking proud, Captive (This image may be licensed either as rights managed or royalty free.)

Andy Rouse / African Lion, (Panthera leo), female hunting, Masai Mara, Kenya, Africa,

Andy Rouse / African lion, (Panthera leo), male, Masai Mara, Kenya, Africa,

Andy Rouse / African Lion, (Panthera leo), female hunting, Masai Mara, Kenya, Africa,

Andy Rouse / RF - African Lion, (Panthera leo), female with cub, Masai Mara, Kenya, Africa,

Ann & Steve Toon / RF - Lion (Panthera leo) male running in desert, Kgalagadi Transfrontier Park, South Africa. (This image may be licensed either as rights managed or royalty free.)

Lucas Bustamante / Female African lion (Panthera leo) face portrait, Etosha National Park, Harare Province, Namibia.

Lucas Bustamante / Four Galapagos sea lions (Zalophus wollebaeki) sleeping on beach, Floreana Island, Galapagos, Endangered species.

Lucas Bustamante / African lion (Panthera leo) resting, Etosha National Park, Harare Province, Namibia.

David Fleetham / California sea lions (Zalophus californianus) playing in a kelp forest off Santa Barbara Island, California, USA.

David Fleetham / California sea lions (Zalophus californianus) playing in a kelp forest off Santa Barbara Island, California, USA.

Bence Mate / African lion (Panthera leo) at waterhole at night, Mkuze, South Africa Third place in the Nature Portfolio category of the World Press Photo Awards 2017.

Neil Aldridge / Lion cub (Panthera leo) calling to its mother from the raised deck of a tourist lodge in the middle of the Busanga Plains, Kafue National Park, Zambia. Vulnerable species.

Neil Aldridge / Lion cub (Panthera leo) playfully attacking its mother as she drags her puku antelope prey across burnt Busanga Plains, Kafue National Park, Zambia. Vulnerable

Neil Aldridge / African lion (Panthera leo) male lying in the middle of the Busanga Plains, Kafue National Park, Zambia. Vulnerable

Neil Aldridge / Lioness (Panthera leo) yawning in early morning light on Kariega Game Reserve, South Africa.

Neil Aldridge / African lion (Panthera leo) male glancing over its shoulder on Northern Tuli Game Reserve, Botswana. Vulnerable species. This lion was shot illegally by South African farmers shortly after the photogr...

Anup Shah / Lion (Panthera leo) male approaching, Maasai Mara National Reserve, Kenya. Taken with remote wide angle camera.