Male black grouse (Lyrurus tetrix) fighting on snow covered field, Finland

Male black grouse (Lyrurus tetrix) fighting on snow covered field, Finland

Male black grouse (Lyrurus tetrix) fighting on snow covered field, Finland

Male Pacific leaping blennies (Alticus arnoldorum), territorial display in tide pool, Marquesas, French Polynesia, South Pacific, Pacific

Lava lizard (Microlophus spp) courtship behavior in the Galapagos Islands Archipelago, UNESCO World Heritage Site, Ecuador, South America

Lava lizard (Microlophus spp) courtship behavior in the Galapagos Islands Archipelago, UNESCO World Heritage Site, Ecuador, South America

Adult bull southern elephant seals (Mirounga leonina) fighting for breeding grounds on South Georgia Island, Southern Ocean

Black-browed albatross (Thalassarche melanophrys) breeding colony on Carcass Island in the Falkland Islands

Adult male mudskipper (Periophthalmus spp,) territorial display at low tide, Bako National Park, Sarawak, Borneo, Malaysia, Southeast Asia, Asia

Rock shag (Phalacrocorax magellanicus), pair exhibiting courtship behavior near New Island in the Falkland Islands, South America

Adult Subantarctic Skua (Catharacta antarctica lonnbergi) on tussac at Salisbury Plain on South Georgia Island, Polar Regions

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

Lava lizard (Microlophus spp) in the Galapagos Islands Archipelago, UNESCO World Heritage Site, Ecuador, South America

The endemic Galapagos marine iguana (Amblyrhynchus cristatus) in the Galapagos Island Archipelago, UNESCO World Heritage Site, Ecuador, South America

Lava lizard (Microlophus spp) in the Galapagos Islands Archipelago, UNESCO World Heritage Site, Ecuador, South America

Blue footed booby (sula nebouxii) incubating eggs at Punta Pitt, San Cristobal Island, Galapagos, UNESCO, Ecuador

Adult bull Steller sea lions (Eumetopias jubatus), territorial display at the Solomon Gulch Hatchery, Valdez, Alaska, United States of America, North America

Adult bull Steller sea lion (Eumetopias jubatus), territorial display at the Solomon Gulch Hatchery, Valdez, Alaska, United States of America, North America

Adult bull Steller sea lions (Eumetopias jubatus), territorial display at the Solomon Gulch Hatchery, Valdez, Alaska, United States of America, North America

Cape Sugarbird (Promerops cafer), calling in territorial display, Western Cape, South Africa, July

Cape Sugarbird (Promerops cafer), waving tail in territorial display, Western Cape, South Africa, July