Three leopard sharks made history. Off the coral-rich shores of New Caledonia, in the blue quiet of Abore Reef, they showcased an unprecedented sexual behavior.
Dr. Hugo Lassauce, a marine biologist from the University of the Sunshine Coast (UniSC), was snorkeling as part of a research mission to monitor wild shark behavior. He had seen brief signs of shark courtship before. But on this particular day, something rare happened.
“I spotted a female with two males grasping her pectoral fins on the sand below me,” Lassauce told Cosmos Magazine. “I told my colleague to take the boat away to avoid disturbance, and I started waiting on the surface, looking down at the sharks almost motionless on the sea floor.”
He floated above them, his camera ready, his body shivering in the water for nearly an hour. Then it happened.
110 Seconds That Changed What We Know About Leopard Sharks
In a precise and quiet sequence that unfolded over 90 minutes, the two males alternated in mating with the female. The actual act lasted just 110 seconds—63 for the first male, 47 for the second. Afterwards, the males collapsed on the seafloor, exhausted. The female swam away, bearing visible wounds on her pectoral fins.
This marked the first documented observation of wild copulation in the Indo-Pacific leopard shark (Stegostoma tigrinum). The leopard shark is an elusive and endangered species. Its reproductive habits were, until now, only witnessed through an aquarium glass. It was also one of the most unusual mating displays ever observed in sharks.
Leopard sharks are found across the Indo-West Pacific from East Africa to the coastal reefs of Australia and the Pacific Islands. Yet despite this wide range, they remain a mystery in the wild. Their numbers have plummeted in Southeast Asia and the western Indian Ocean, largely due to overfishing and habitat destruction. In many regions, they have vanished entirely.
“Outside of Australia—where they are quite healthy—the species is considered endangered due mostly to overfishing,” said Dr. Christine Dudgeon, a UniSC marine ecologist and co-author of the new study, published in the Journal of Ethology. “Not just for fins but for other products, including a more recent discovery of the use of their skin for lining walls in luxury yachts,” she told the ABC.
Why This Matters for Shark Conservation
Until now, most of what scientists knew about leopard shark reproduction came from captivity. Males have been observed grasping females with their mouths, thrusting, and inserting their claspers (elongated reproductive organs). But these behaviors had never been captured in the wild.
The mating occurred in a shallow reef zone just 15 kilometers off the coast of Nouméa. This is a part of the South Pacific archipelago where Lassauce and colleagues had been conducting long-term fieldwork under the ReShark Collective. ReShark is a global effort to rewild endangered shark populations.
“This evidence suggests the site in New Caledonia is a critical mating habitat,” said Dudgeon in Cosmos Magazine. “It can inform management and conservation strategies as well as help us understand population dynamics and reproductive behaviors more widely.”
And those dynamics may be surprisingly complex.
“It’s surprising and fascinating that two males were involved sequentially on this occasion,” Dudgeon also told The Guardian. “From a genetic diversity perspective, we want to find out how many fathers contribute to the batches of eggs laid each year by females.”
We don’t know much about how female sharks select mates. We don’t know if they pick one male or tolerate multiple ones, for instance. This behavioral insight can shed light on how populations maintain genetic diversity in increasingly fragmented habitats.
These discoveries also have practical applications. Multiple countries, including Australia, are now exploring artificial insemination techniques to reintroduce leopard sharks into areas where they’ve disappeared. Knowing how the species mates naturally, including the timing and behavior, is critical to replicating that success in lab settings.
Even the smallest details matter. The study noted a “structured sequence” of behavior. It involves prolonged positioning, synchronized stillness on the seafloor, and the use of siphon sacs—paired organs that help force sperm into the female during mating. These are clues to a choreography that has evolved over millions of years, yet remained elusive.
The Secret Lives of Sharks
Lassauce, for his part, had waited weeks for such a moment.
“We have been seeing and observing some courtship events [over several weeks] where the male will try a little bit with the female, but nothing happened,” he told ABC. “This day it just happened.”
Sharks have roamed the oceans for over 400 million years, yet many of their behaviors remain as enigmatic as the deep they inhabit.
Unlike marine mammals such as dolphins, which engage in frequent and observable social displays, sharks don’t build nests, sing to attract mates, or engage in elaborate courtship rituals (that we know of). For many species, including the leopard shark, sexual reproduction is a brief, raw, and rarely witnessed affair. The recent observation off the coast of New Caledonia, where two males were documented mating sequentially with a single female, offers a rare and invaluable window into the reproductive lives of these ancient predators. This event, lasting a mere 110 seconds, has significantly expanded our understanding of leopard shark behavior and underscored the complexities of their mating strategies.
The challenges of studying shark reproduction in the wild are immense. Many species are solitary, inhabit remote or deep-water environments, and are highly migratory. The act of mating itself is often a brutal affair. Male sharks possess two claspers, modified pelvic fins used to transfer sperm to the female. To gain purchase during copulation, males will often bite the female’s pectoral fins or back, a behavior that can leave her with significant wounds. In an evolutionary response, the skin of some female sharks is more than twice as thick as that of the males.
Shark reproductive strategies are remarkably diverse. Some species are oviparous, laying eggs encased in a tough, leathery pouch often called a “mermaid’s purse.”Others are viviparous, giving birth to live young that have been nourished through a placental connection, much like mammals. A third strategy is ovoviviparity, where the eggs hatch inside the mother’s body, and the pups are born live. In some ovoviviparous species, a grim form of intrauterine cannibalism occurs, where the largest and strongest embryo consumes its siblings in the womb. Remarkably, some female sharks are also capable of parthenogenesis, or “virgin birth,” a form of asexual reproduction where an embryo develops from an unfertilized egg.
The brief, fleeting moments witnessed in the waters of New Caledonia serve as a powerful reminder of how much we still have to learn about the secret lives of sharks.
The footage recorded at Abore Reef is available here.
