Sharktopus Encounter: No, It's Not An April Fool's Joke.

Forbes

01-04-2025

'One of the best things about being a marine scientist is that you never know what you might see next in the sea.' That was certainly the case for marine biologist Professor Rochelle Constantine and her colleagues at the University of Auckland, who did not expect to find an octopus riding a shark. But that's exactly what they witnessed in December 2023 while surveying the waters of the Hauraki Gulf near Kawau Island, off the northern coast of New Zealand's North Island.
The Hauraki Gulf is a vast and ecologically rich body of water that stretches from Auckland to the Coromandel Peninsula and Great Barrier Island. The gulf's dynamic environment includes deep channels, sandy bays, and rocky reefs, making it an important habitat for both coastal and pelagic species. It is also a significant area for conservation efforts, as human activity, climate change, and overfishing have impacted its ecosystems.
'A large metallic grey dorsal fin signalled a big shark, a short-fin mako. But wait, what was that orange patch on its head? A buoy? An injury?" Constantine recalls. "We launched the drone, put the GoPro in the water and saw something unforgettable: an octopus perched atop the shark's head, clinging on with its tentacles.'
It was a startling discovery. Afterall, shortfin mako sharks, the fastest sharks in the world, can reach speeds of up to over 31 mph (50 kph). They typically hunt fast-moving fish like tuna and mackerel near the ocean's surface, while octopuses tend to stick to the seafloor, preferring rocky reefs and hiding spots. The two species don't often cross paths, making this… well, encounter, especially unusual. 'We really don't know how this octopus, that lives on the seabed, came across this [10-foot-long]
An underwater camera confirmed the enormous Māori octopus (Octopus maorum) was alive and actively moving. The scientists observed the sharktopus — the unofficial nickname for the peculiar duo — for 10 minutes. To their surprise, the mako showed no signs of stress. Normally, a shark with something foreign on its body would react aggressively, twisting and shaking to remove it. But this shark swam along calmly, seemingly unbothered. 'We moved on after 10 minutes so I can't tell you how what happened next. The octopus may have been in for quite the experience,' Constantine said.
The Māori octopus is one of the largest octopus species found in the waters around New Zealand and southern Australia. Weighing up to 26 pounds (12 kg) and with an arm span reaching nearly 10 feet (3 m), this formidable cephalopod is known for its intelligence, adaptability, and ability to change color and texture to blend into its surroundings. It primarily inhabits coastal and deep-sea environments, preferring rocky reefs and sandy seafloors where it can hunt crabs, fish, and other small marine creatures. Like other octopuses, it has a short lifespan — typically only a couple of years — and reproduces only once before dying. Its nocturnal nature and remarkable camouflage abilities make it a challenging species to study, adding to the intrigue surrounding this fascinating predator.
What exactly led to this encounter remains an open question. Constantine speculated that the octopus might have been using the shark as a temporary refuge, perhaps to escape a predator or avoid detection. Octopuses are known for their intelligence and problem-solving abilities, so it's not impossible that this one saw an opportunity and took it. Another theory is that the mako may have ventured unusually close to the seafloor, where the octopus could have mistaken it for a rock or another surface to hide on. The shark's slow movement may have allowed the octopus to stay latched on, but if the mako had picked up speed, the octopus likely would have been forced off. And if that happened, the shark, which preys on squid and other cephalopods, might have taken the opportunity to make a meal out of its unexpected passenger.
While rare, cephalopods interacting with sharks isn't unheard of. In some cases, octopuses have been observed defending themselves from sharks by wrapping their arms around the predator's head, sometimes even suffocating smaller sharks. But this brief partnership remained peaceful, at least for the duration of the scientists' observations.
Shortfin makos are formidable predators, but they're also highly threatened. Listed as Endangered by the International Union for Conservation of Nature, these sharks face significant pressure from commercial fishing, particularly due to bycatch and demand for their meat and fins. Despite their speed and hunting prowess, they are vulnerable to human activity, with populations in decline due to overfishing. Constantine hopes that encounters like this one highlight the importance of conserving marine species, not just for their ecological roles but for the incredible, unpredictable behaviors they exhibit in the wild: 'By supporting conservation initiatives, we can help to ensure that such extraordinary moments keep happening.'
The shark and octopus eventually parted ways, with the cephalopod likely dropping off into the depths and the mako continuing on its course. The sighting left the researchers with more questions than answers… but that's the beauty of studying the ocean. It is vast, mysterious, and full of surprises.