Tony Wu / Humpback whales (Megaptera novaeangliae) in a heat run, with six males competing for the attention of a female that already has a calf. Vava'u, Kingdom of Tonga

Tony Wu / Humpback whales (Megaptera novaeangliae) engaged in courtship, with the male hovering above the female. Vava'u, Tonga, Pacific Ocean.

Tony Wu / Humpback whale (Megaptera novaeangliae), fluke of female with male calf playing below, Vava'u, Tonga, Pacific Ocean.

Tony Wu / Humpback whale (Megaptera novaeangliae) female close up, Vava'u, Kingdom of Tonga. Pacific Ocean.

Lucas Bustamante / Humpback whale (Megaptera novaeangliae) fluke above the water as it dives, Machalilla National Park, Manabi, Ecuador.

Alex Mustard / Whitetip shark (Carcharhinus longimanus) head on beneath the surface. Rocky Island, Egypt. Red Sea

Jordi Chias / Grey reef sharks (Carcharhinus amblyrhynchos) in the south pass of Fakarava Tuamotus, French Polynesia, South Pacific

Alex Mustard / Great hammerhead shark (Sphyrna mokarran) female at night with Bar jacks (Caranx ruber), South Bimini, Bahamas. The Bahamas National Shark Sanctuary. Gulf Stream, West Atlantic Ocean.

Jordi Chias / Angular roughshark (Oxynotus centrina) a deepsea species living at 80-300m depth, caught by fishermen and released, Costa Brava, Catalunya, Spain, Mediterranean Sea

Edwin Giesbers / Male Lion (Panthera leo) portrait, close-up of face, captive, occurs in Africa.

Edwin Giesbers / Lion (Panthera leo) portrait of two lionesses, captive, occur in Africa.

Andy Rouse / Bengal tiger (Panthera tigris tigris) female 'Noor T19' bringing down Sambar deer (Rusa unicolor) Ranthambhore, India. Sequence 3 of 18.