Marie Read / Canada geese (Branta canadensis) two during territorial fight in early spring, Ithaca. New York, USA

Marie Read / American avocets (Recurvirostra americana) two during aggressive (territorial) encounter, Bear River Migratory Bird Refuge, Utah, USA, May.

Donald M. Jones / Northern Pintail (Anas acuta) males flying with female in spring courtship display, Montana

Nick Garbutt / Jaguar (Panthera onca) female running along a sand spit chasing after a caiman. Northern Pantanal Cuiaba River, Mato Grosso, Brazil.

Daniel J. Cox / Gray Wolf (Canis lupus) pair predating female Elk (Cervus elaphus) crossing river, Alum Creek, Yellowstone National Park, Wyoming, sequence 1 of 4

Terry Whittaker / Domestic cat chasing a Red fox (Vulpes vulpes) in an urban garden, Greater Manchester, UK, August 2017. Filmed using a camera trap.

Remi Masson / Pair of Pumpkinseeds (Lepomis gibbosus) mating, male chasing other individuals away, River Rhone, Rhone-Alpes, France, June.

John Chan / Male California Least Tern (Sternula antillarum browni) courting a female, presenting a fish before chasing off another male, Huntington Beach, California, USA, May.

John Waters / Slow motion clip of a Mallard (Anas platyrhynchos) duckling chasing and catching Mayfly (Ephemeroptera) emerging from River Kennet, Hungerford, Berkshire, England, UK, June.

Alan Murphy/ BIA / Northern Caracara (Caracara cheriway) chasing sub-adult with prey, Texas

John Waters / Male Shoveler (Anas clypeata) chasing other males away from his mate, Greyale RSPB Reserve, Somerset Levels, England, UK, February.

Five Films / Female Grey seal (Halichoerus grypus) defending pup on beach, chasing male away, Horsey, Norfolk, November.