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

Adult black-legged kittiwake (Rissa tridactyla) in combat with a second kittiwake near Alexander Island, Franz Josef Land, Russia, Arctic Ocean, Eurasia

Juvenile grey heron (Ardea cinerea) in flight, escaping from an aggressive rival in a territorial dispute, Rutland Water, Rutland, England, United Kingdom, Europe

Adult Nazca booby (Sula grantii) feeding on halfbeak, and defending its catch against a frigatebird, in the Galapagos Island Archipelago, UNESCO World Heritage Site, Ecuador, South America

Northern giant petrels (Macronectes halli) fighting over the scavenging rights to a dead elephant seal pup at Royal Harbor, South Georgia

Northern giant petrels (Macronectes halli) fighting over the scavenging rights to a dead fur seal pup at St. Andrews Bay, South Georgia

Female southern elephant seal (Mirounga leonina) with newborn pup as skuas (Catharacta antarctica) fight for the afterbirth, South Georgia

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

Adult black-legged kittiwake (Rissa tridactyla) in combat with a second kittiwake near Alexander Island, Franz Josef Land, Russia, Arctic Ocean, Eurasia

Southern elephant seal (Mirounga leonina) mating behavior on South Georgia Island, Southern Ocean

Southern elephant seal (Mirounga leonina) mating behavior on South Georgia Island, Southern Ocean

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

Adult Brunnich's guillemots (Uria lomvia) in a territorial dispute at Alkefjellet, Spitsbergen, Svalbard, Norway, Europe

A combative male iguana bloodied in territorial battle. Santiago Island, Galapagos.S(marine iguana)S(territorial dispute)S(Galapagos)S(UW)

Red fox (Vulpes vulpes) males in territorial confrontation. Montreal Botanical Garden. Quebec. Canada