Alex Mustard / A diver explores Silfra Canyon, a deep fault filled with fresh water in the rift valley between the Eurasian and American tectonic plates at Thingvellir National Park, Iceland. May 2011. In this phot...

Nigel Cattlin / Tungro virus (Rice (Oryza sativa) tungro bacilliform virus) on diseased, damaged Rice (Oryza sativa) plot, Philippines

Nick Hawkins / North Atlantic right whale (Eubalaena glacialis) tail fluke, diving to feed in the Gulf of Saint Lawrence, Canada. Endangered species. July

Nick Hawkins / Fishing ropes wrap around the head and mouth, damaging the baleen of a severely entangled North Atlantic right whale (Eubalaena glacialis) in the Gulf of Saint Lawrence, Canada. Fishing gear entanglem...

Nick Hawkins / Fishing ropes wrap over the blowhole of a severely entangled North Atlantic right whale (Eubalaena glacialis) in the Gulf of Saint Lawrence, Canada. Fishing gear entanglement is a leading cause of dea...

Nick Hawkins / Head of a North Atlantic right whale (Eubalaena glacialis) showing callosities, patches of roughened skin that are unique to each whale. Gulf of Saint Lawrence, Canada. IUCN Status: Endangered. August

John Chan / Two male Southern Pacific rattlesnakes (Crotalus oreganus helleri) fighting during mating season. This behaviour is known as a "combat dance", and is used to determine dominance and the right to mate...

Espen Bergersen / Aerial shot of a group of Killer whales (Orcinus orca) tail slapping, shot pans to the right, Skjervoy, Troms, Norway, November.

Marie Read / Wood Ducks (Aix sponsa), females behave aggressively toward a male (second from right) that is trying to join them on a floating log, autumn, New York, USA, October.

David Gallan / Two Southern right whales (Eubalaena australis) playing in shallows, taken with drone, Tathra Beach, New South Wales, Australia, August.

Hiroya Minakuchi / Southern Right Whale (Eubalaena australis) sailing at sunset, Peninsula Valdez, Argentina

Agustin Esmoris / Southern Right Whale (Eubalaena australis) surfacing with Kelp Gull (Larus dominicanus) picking off lice, Chubut, Argentina, sequence 1 of 4