Tony Wu / Spinner dolphin (Stenella longirostris) male leaping out of the water. The protruding tip of the dolphin's penis is just visible. Sri Lanka. Indian Ocean.

Tony Wu / Spinner dolphin (Stenella longirostris) leaping exceptionally high into the air, Sri Lanka.

Tony Wu / Spinner dolphin (Stenella longirostris) juvenile surfacing next to its mother, Sri Lanka.

Tony Wu / Spinner dolphin (Stenella longirostris) launching itself out of the water. Sri Lanka.

Alex Mustard / Spinner dolphins (Stenella longirostris) female mates with a male below, while another male accompanies. The two males were taking it in turn to mate with her. Sataya Reef, Fury Shoal, Egypt. Red Sea

Alex Mustard / Spinner dolphins (Stenella longirostris) pod swimming over a shallow sandy lagoon in a coral reef. Sataya Reef, Fury Shoal, Egypt. Red Sea

Claudio Contreras / Pantropical Spotted Dolphin (Stenella attenuata) breaching, viewed from above, Socorro Island, Revillagigedo Archipelago Biosphere Reserve / Archipielago de Revillagigedo UNESCO Natural World Heritage...

Doug Perrine / Hawaiian / Gray's Spinner Dolphin (Stenella longirostris longirostris) pod, Ho'Okena, South Kona, Hawaii , USA, Central Pacific Ocean.

Doug Perrine / Pod of Hawaiian / Gray's Spinner Dolphins (Stenella longirostris longirostris), off Ho'okena Beach, South Kona, Hawaii , USA, Central Pacific Ocean.

Doug Perrine / Pod of Hawaiian / Gray's Spinner Dolphins (Stenella longirostris longirostris), off Ho'okena Beach, South Kona, Hawaii , USA, Central Pacific Ocean.

Doug Perrine / Hawaiian / Gray's Spinner Dolphin (Stenella longirostris longirostris) mother with calf that has a round wound from the bite of a cookie cutter shark, off Ho'okena Beach, South Kona, Hawaii , USA, Cen...