First Recording of Leopard Shark Mating ‘Threesome’ in the Wild

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First-Ever Recording of Leopard Sharks Mating in the Wild Reveals Rare ‘Threesome’

For the first time ever, scientists have captured leopard sharks mating in the wild — and the footage revealed an unexpected “threesome” involving two males and a single female.

The rare encounter was filmed by Hugo Lassauce, a marine biologist at Australia’s University of the Sunshine Coast, during a research dive in New Caledonia on July 12, 2024. The video, published this week in the Journal of Ethology, is believed to be the first confirmed observation of leopard shark copulation outside captivity.

A Rare Window Into Shark Behavior

“Mating events in sharks are extremely rare to witness,” Lassauce told CNN. Until now, researchers had only documented courtship interactions—such as males chasing females—but not the full act of mating in the wild.

Leopard sharks (Stegostoma tigrinum), found in the Indian Ocean and western Pacific, are listed as endangered by the International Union for Conservation of Nature. Populations have been in steady decline, making observations of their natural reproductive behavior particularly valuable for conservation.

The Encounter
While diving at a known shark aggregation site in New Caledonia, Lassauce witnessed two males gripping a female’s pectoral fins with their mouths. Recognizing the significance, he filmed for 90 minutes.

The sharks—each about 2.3 meters (7.6 feet) long—remained on the seafloor while the female occasionally tried to break free. Over the course of an hour:

One male mated with the female for 63 seconds.
The second male followed, copulating for 47 seconds.
Afterward, the exhausted males collapsed on the seabed while the female swam away.
“Holding a female while she’s resisting and mating while swimming drains the males completely,” Lassauce explained. “After copulating, the male is just out of it, needing to rest on the seafloor for a few minutes.”

Conservation Significance
Leopard sharks have mostly been studied in captivity, where they are known to reproduce both sexually and through parthenogenesis (a process where females produce offspring without males). This first wild observation could help refine artificial insemination techniques and inform broader conservation efforts, Lassauce said.

He works with the ReShark international initiative, focusing on shark reproduction, egg-laying habitats, and the movements of newly hatched leopard sharks in the wild.

A Surprising Discovery
Christine Dudgeon, senior research fellow at the University of the Sunshine Coast and co-author of the paper, called the sequential involvement of two males “surprising and fascinating.”

From a conservation genetics perspective, she added, the finding raises questions: “How many fathers contribute to each batch of eggs? That has big implications for genetic diversity.”

Emily Humble, a research fellow at the University of Edinburgh’s Roslin Institute, who was not involved in the study, said the discovery adds to leopard sharks’ already unusual biology.

“Not only can females reproduce without males, but they also appear to mate with multiple partners,” Humble noted. “Genetic studies testing for multiple paternity will be key to understanding how these strategies influence diversity in this endangered species.”

For now, this groundbreaking footage marks a milestone in marine science — offering a rare glimpse into the intimate lives of one of the ocean’s most enigmatic shark species.

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