Scuba divers love the underwater behavior of a host of marine animals, but there is perhaps no behavior more (ahem) alluring than the mating rituals of creatures both large and small. From the provocative promiscuity of dumpling squid and the magical dance of mandarinfish, to the exhausting hookups of loggerhead turtles and gentle nuzzlings of porcupinefish, the behavior of marine animals in the act of reproductive lovemaking is a fascinating subject for voyeuristic divers and underwater photographers.

Nudibranchs are hermaphroditic, which is beneficial to these often-solitary, slow-moving animals. When one nudibranch passes by another one, it’s sure to be a potential mate, as it has all the right parts. To mate, nudis — like this colorful pair photographed off the Nusa Tenggara islands in Indonesia’s Komodo National Park — line up side by side so their right sides are together, as that is where the reproductive organs are. Each passes a sperm packet to the other, and both lay eggs, often on top of their prey.

It’s not uncommon for two — or sometimes more — male loggerhead turtles to court a single female, like this threesome photographed off Key Largo in the Florida Keys. Females undertake the exhausting journey to nest on shore a few weeks after mating.

After dusk, male porcupinefish search for females, and court them by nuzzling and nudging their belly, like this pair found in the Red Sea’s Ras Mohammed Park. The male pushes the female toward the surface, and then both release their eggs and sperm simultaneously.

Mandarinfish live in small areas of sheltered lagoons and inshore reefs in the western Pacific. To spawn, a female joins the male, resting on his pelvic fin, and the pair rises slowly to about three feet above the reef where a cloud of eggs and sperm is released. This pair was found in Bunaken.

Dumpling squid are known to mate for up to three hours, and during that time the male physically restrains the female. Found off southern Australia, these cephalopods live for less than a year and spend their last few months mating with as many partners as possible.

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Updated on Feb. 13, 2017