Latest news with #Orcinusorca
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First Post
10-07-2025
- Science
- First Post
Why are orcas gifting food to humans across the oceans?
Over two decades, orcas have been observed offering prey to humans in 34 recorded encounters across the globe. From stingrays to sea turtles, killer whales appear to gift food, then wait and watch. Scientists now believe this rare and deliberate behaviour reveals complex social intent, curiosity and possibly interspecies connection read more Orcas come up for air in the Norwegian Sea, Norway, January 3, 2024. File Image/Reuters A newly published study has shed light on an unusual and rarely seen behaviour in killer whales (Orcinus orca): voluntarily presenting dead prey to humans. Over a span of 20 years, researchers documented 34 such interactions, offering the first scientific insight into a phenomenon that has perplexed and intrigued marine biologists. These incidents, observed off the coasts of California, New Zealand, Norway, Canada and Patagonia, involved orcas approaching humans either in the water, on boats, or near the shore, and intentionally delivering items such as fish, birds, rays or marine mammals. STORY CONTINUES BELOW THIS AD The study was published in the Journal of Comparative Psychology and authored by scientists from Canada, New Zealand and Mexico, including Jared Towers, executive director of the Canadian research organisation Bay Cetology, who also witnessed several of these encounters firsthand. How a unique behavioural pattern emerged across oceans The research team compiled records of orcas approaching humans without prompting, either by swimmers, boaters or shore observers. In total, 11 instances involved individuals in the water, 21 were from boats and two occurred onshore. Remarkably, in all but one event, the whales lingered near the humans after dropping the prey, apparently observing what would happen next. The food offerings included 18 different species, among them stingrays, seals, birds, otters, jellyfish, starfish, grey whale blubber and even sea turtles and seaweed. Some encounters were captured on video; others were described in interviews with eyewitnesses and scientists. In seven cases, when the initial offering was declined or ignored, the orcas attempted the gesture again, sometimes multiple times. In three recorded incidents, when humans returned the prey to the whale, the whale again delivered it back. Among the more striking cases was a young male orca in New Zealand named Funky Monkey, who repeatedly approached a researcher with a stingray balanced on his head. In Norway, a whale appeared to offer jellyfish to a diver. Jared Towers himself was approached in 2015, while documenting a pod feeding on seabirds in Alert Bay, Canada. STORY CONTINUES BELOW THIS AD Two orcas — Akela and her younger brother Quiver — each brought him a dead bird, dropped it nearby, and stayed close before retrieving their prey and swimming away. Another such encounter occurred in 2018, when a young female delivered a harbour seal pup. Behind the orcas' behaviour The orcas involved were all generalist predators, typically hunting a wide variety of surface-dwelling marine animals. Researchers noted that no such behaviour was observed in deep-feeding orca groups that exclusively eat fish, even though those populations are also accustomed to human presence. This distinction may be key to understanding the emergence of this practice. A killer whale member of the Bigg's orca T65B pod is seen in the Salish Sea near Eastsound, Washington, US, July 7, 2023. File Image/Reuters According to the research, generalist orca pods often work together to take down large prey, sometimes leaving them with more food than they can consume. In such scenarios, there's an opportunity to either discard, play with, or repurpose the excess prey. 'Orcas often share food with each other — it's a prosocial activity and a way that they build relationships with each other,' said Towers. 'That they also share with humans may show their interest in relating to us as well.' STORY CONTINUES BELOW THIS AD The study highlights that food-sharing among orcas is common within pods and may function as a social bonding mechanism. Extending this behaviour towards humans could reflect an adaptation or extension of those social instincts. Notably, the research also suggests these food offers might allow the whales to engage in exploratory behaviour, or 'practise learned cultural behaviour' in new, interspecies contexts. What orca history tells us Killer whales are known for their sophisticated social behaviours, language dialects and cultural traditions. In the wild, they have been observed gently interacting with one another through gestures like nibbling each other's tongues or synchronised swimming, suggesting high levels of social cohesion and communication. This is not the first time that orcas have worked in concert with humans. Historical records show that orca pods once cooperated with Indigenous Australian and European whalers, helping them corral baleen whales in exchange for access to their meat and tongues. However, that was a mutualistic relationship with clear benefit for the orcas. The events described in this new study are different — the orcas are giving away food without any visible incentive or gain. STORY CONTINUES BELOW THIS AD Towers and his colleagues suggest that such interactions may indicate generalised altruism — actions that benefit another being without direct benefit to oneself. The presence of such behaviours could also hint at theory of mind — the ability to attribute mental states, like intentions or desires, to others. 'They're actively learning about us by testing the waters,' Towers explained. 'Curiosity is one of the things that reduces uncertainty.' Are orcas forming bonds with humans? In many of the encounters, the animals seemed interested in observing human reactions and often re-engaged when ignored, suggesting a deeper purpose. However, scientists also caution that manipulation cannot be ruled out, though it's unclear what goal that manipulation would serve. 'This behaviour may represent some of the first accounts of a wild predator intentionally using prey, and other items, to directly explore human behaviour,' the study authors noted. The researchers believe the act of gifting may provide short- or long-term emotional or intellectual benefits to the animals, adding, 'none of which are mutually exclusive.' The study concludes that given orcas' high intelligence, strong social ties, and cooperative nature, it is plausible that these food-sharing behaviours could be tied to cognitive experimentation, curiosity or even an attempt to understand humans better. STORY CONTINUES BELOW THIS AD Also Watch: With inputs from agencies
Yahoo
18-06-2025
- Science
- Yahoo
Great White Sharks Were Scared From Their Habitat by Just 2 Predators
No sea creature inspires terror – rightly or wrongly – as much as the white shark does. With its sleek body optimized for hunting, razor sharp teeth, and its (somewhat undeserved) reputation for enjoying human flesh, the 'great' white (Carcharodon carcharias) is widely regarded as one of the ocean's top predators. And that's true, it is – but there's something even the great white fears. Watch the video below for a summary of the research that revealed a predator other predators fear: From 2017, scientists have documented that the sharks have made themselves extremely scarce off the coast of South Africa, where they usually congregate. Initially, the strange disappearance was blamed on human activity, such as overfishing. But, in 2022, research confirmed in detail the true culprit: a pair of orcas (Orcinus orca), nicknamed Port and Starboard for the distinctive kinks in their dorsal fins, hunting the sharks and slurping out their delicious, nutritious, vitamin-rich livers. Once upon a time, the fishing town of Gansbaai on the South African coast was something of a mecca for shark-spotters – so heavily populated with the predators that nearby Dyer Island is considered the great white shark capital of the world. Over the last few years, however, the sharks' presence has been diminishing. In addition, since 2017, at least nine great white sharks have washed ashore at Gansbaai, several of them missing livers (and some without their hearts) – the hallmark of an orca attack. And white sharks aren't the only prey. Port and Starboard have been implicated in a broadnose sevengill shark killing spree, wiping out at least 17 in a single day. The wounds on these sharks are distinctive, and have been traced to the same pair of orcas. It's likely, scientists believe, that the pair are responsible for many more great white deaths that haven't washed ashore. We know from other studies that the presence of orcas can drive great white sharks away pretty adroitly. One study in 2020 found that great whites will scarper away, without fail, from preferred hunting waters off the coast of San Francisco if an orca makes an appearance in the region. In a study from 2022, using long-term sighting and tracking data from tagged sharks, a team of scientists led by marine biologist Alison Towner of the Dyer Island Conservation Trust found that orcas are the reason sharks are starting to avoid what used to be some of their favorite spots. "Initially, following an orca attack in Gansbaai, individual great white sharks did not appear for weeks or months," Towner explained. "What we seem to be witnessing though is a large-scale avoidance (rather than a fine-scale) strategy, mirroring what we see used by wild dogs in the Serengeti in Tanzania, in response to increased lion presence. The more the orcas frequent these sites, the longer the great white sharks stay away." Over the course of five years, the team tracked 14 sharks that had been GPS tagged as they fled the area when orcas were present. Sightings of great white sharks are also down, quite significantly, in several bays. This is a huge deal. Only twice before had great white sharks been noted as absent for a week or more in Gansbaai since record-keeping began: a period of one week in 2007, and a period of three weeks in 2017. The new absences, the researchers said, are unprecedented. They're also ongoing. In a paper published earlier this year, Towner and her colleagues documented two sightings of Port and Starboard attacking sharks and eating their livers. Worryingly, these attacks are altering the ecosystem. In the absence of great white sharks, copper sharks (Carcharhinus brachyurus) are moving in to fill the vacant ecological niche. These sharks are preyed upon by great whites; with no great whites around, the orcas are hunting the coppers instead. And, notably, they're doing so with the skill of predators who have had experience in hunting large sharks, the researchers said. "However, balance is crucial in marine ecosystems, for example, with no great white sharks restricting Cape fur seal behavior, the seals can predate on critically endangered African penguins, or compete for the small pelagic fish they eat. That's a top-down impact, we also have 'bottom up' trophic pressures from extensive removal of abalone, which graze the kelp forests these species are all connected through," Towner said. "To put it simply, although this is a hypothesis for now, there is only so much pressure an ecosystem can take, and the impacts of orcas removing sharks, are likely far wider-reaching." It's also worth considering the reasons why orcas might be hunting sharks. Their livers are rich sources of nutrition, huge, plump, and full of fats and oil that the sharks use to fuel their epic migratory journeys across the ocean. But it's unclear how the orcas figured this out, or why they might seek the shark livers as a preferred source of nutrition. It's possible that some orcas are adapting to preferentially hunt sharks, perhaps in response to declining numbers of their preferred prey. An unrelated pod in the Gulf of California has developed its own techniques for hunting whale sharks, too. However, given that great white populations are declining worldwide, the added pressure of an efficient predator is a cause for concern. "The orcas are targeting subadult great white sharks, which can further impact an already vulnerable shark population owing to their slow growth and late-maturing life-history strategy," Towner said. "Increased vigilance using citizen science (e.g. fishers' reports, tourism vessels), as well as continued tracking studies, will aid in collecting more information on how these predations may impact the long-term ecological balance in these complex coastal seascapes." The team's research has been published in the African Journal of Marine Science, and African Journal of Marine Science. An earlier version of this story was published in July 2022. Solid Rock Caught Flowing 1,700 Miles Beneath Surface in Experimental First Hundreds of Mysterious Giant Viruses Discovered Lurking in The Ocean Scientists Just Solved a 100-Million-Year-Old Mystery About Platypus Sex
Yahoo
31-03-2025
- Science
- Yahoo
Orcas Are Terrorizing Sharks, And The Consequences Could Be Profound
A pair of orcas terrorizing white sharks off the coast of South Africa may have captured the popular imagination, but their activities may be quite damaging, new research suggests. Port and Starboard, as the orcas (Orcinus orca) are known, have been documented hunting white sharks (Carcharodon carcharias) off the coast of South Africa for years, handily eviscerating them to feast on their nutritious livers, potentially reducing shark numbers in the area. The impact of a declining shark presence has been difficult to determine, but we may be closer to an answer. Over the last few decades, white sharks have disappeared entirely from False Bay near the Cape of Good Hope – and the cascading effects of the loss of a top predator have been remarkable. "The loss of this iconic apex predator has led to an increase in sightings of Cape fur seals and sevengill sharks, which in turn has coincided with a decline in the species that they rely on for food," says marine ecologist Neil Hammerschlag, formerly of the University of Miami. "These changes align with long established ecological theories that predict the removal of a top predator leads to cascading effects on the marine food web." An ecosystem is a delicate balance maintained by the interaction of the organisms that inhabit it. Although the predators at the top are considered scary by some, removing them from the environment has significant consequences. Suppression of natural predators in Pando forest in Utah, for example, has allowed deer and elk to run riot, feasting on the ancient aspen colony and slowly killing it. For more than 20 years, scientists have been monitoring wildlife populations in False Bay. This meant that they were able to see, in real time, the decline and ultimate disappearance of white sharks from the ecosystem there, and the consequent changes in populations of other species in the food web. From 2000, scientists conducted standardized surveys of white shark sightings at Seal Island, and until around 2015, the shark population was pretty stable. After 2015, however, sightings started to fall dramatically; by 2018, there were no sharks to be seen. The reason for this hasn't been officially confirmed. It's worth noting, however, that white sharks started washing up along the southern coast of South Africa, without their livers, in 2015 – attacks that would later be traced to Port and Starboard. Although the cause of the shark disappearance is yet to be confirmed, we know the effects. White sharks prey on Cape fur seals (Arctocephalus pusillus pusillus). With no sharks around to keep their numbers in check, seal populations boomed. At the same time, sevengill sharks (Notorynchus cepedianus) started appearing – large-bodied sharks that are both prey and competitor to white sharks. As the numbers of Cape fur seals and sevengill sharks rose, populations of the species they prey upon in turn dramatically declined – small fish for the seals, and small sharks for the sevengills. We know, based on other animal population booms, that a sudden increase in food competition between members of the same species can have dire consequences, with individuals taking greater risks to access food, and the weaker individuals starving when they are unable to compete. It may take some time for the ecosystem to recover balance; and, once it does so, it could be very different from the ecosystem it was before. Such changes are pretty normal in the natural world – after all, the world we live in today looks very different from the world of, say, 11,000 years ago, at the end of the last glacial period, or the world 70 million years ago, before the dinosaurs were eradicated. However, understanding what drives such changes in the Anthropocene can help us try to minimize our own impact, and protect vulnerable habitats and the animals that need them to survive. Port and Starboard have been observed hunting white sharks around Gansbaai and Mossel Bay, both further along the southern coast of South Africa. The pair has also been sighted hunting in False Bay, although white sharks are not among the prey observed in that specific area. Nevertheless, it's reasonable to infer that their ongoing mischief at least plays a role in the changes at False Bay. However, we cannot rule out overfishing, pollution, and shark cull programs as contributing factors, either. This is information that is relevant to understanding the wider impact of our own activities. "Future work at this site would benefit from understanding if and how community structure and function may have been altered and the extent to which they will continue to change through time," the researchers write in their paper. "While impacts of apex predator declines are difficult to detect in the wild, especially in marine environments, they are likely more widespread than recognized given the pace and extent of apex predator declines globally." The research has been published in Frontiers in Marine Science. Rock Used as a Doorstop For Decades Found to Be Worth Over $1 Million Antarctic Iceberg Breaks Away to Reveal a Never-Before-Seen Ecosystem Huge Trees Hiding in Plain Sight May Be a Species Totally New to Science
Yahoo
05-02-2025
- Science
- Yahoo
DNA Confirms Orcas Prey Upon One of Australia's Deadliest Marine Predators
It's not just the white sharks off the South African coast of Gansbaai that feel the deep, primal fear known only to prey. For years now, a single pair of orcas (Orcinus orca) has been recorded off the coast of Gansbaai, harrying and hunting the white sharks (Carcharodon carcharias) that make the area one of their homes, slurping out the sharks' nutrient-rich livers, leaving the rest of the carcasses to wash ashore. It now appears that the behavior is more widespread than we knew. In 2023, off the southeastern coast of Australia, half a world away from Gansbaai, the remains of a 4.7-meter (15.4-foot) white shark washed ashore, a gaping hole in its abdomen ringed by ragged tooth marks, and a marked absence of a liver. DNA sequencing has now confirmed that the culprit was none other than an orca. "There were four distinctive bite wounds, one of which was characteristic of liver extraction by killer whale, similar to what has been observed in South Africa," says biologist Isabella Reeves, of Flinders University in Australia. The researchers took swabs from the white shark's bite wounds and sequenced for any genetic material that the predator may have left behind. This confirmed the presence of orca DNA in the main bite, while three other wounds carried traces of DNA from scavenging broadnose sevengill sharks. As we are discovering, the predation by orcas on cartilaginous fish such as sharks and rays isn't uncommon. Orcas are highly adaptable and highly intelligent, and around the world, different groups of orcas have developed their own strategies for hunting and feeding. The strategy developed by the pair named Port and Starboard off the coast of South Africa is fascinating because it involves two such efficient species of marine predator, but a growing body of evidence suggests that it is not unique. Orcas in the Gulf of Mexico prey on whale sharks, for instance. And orcas off the coast of Australia have been recorded preying on multiple species of shark, including porbeagles, makos, blue sharks, tiger sharks, and ground sharks. But the discovery of the white shark carcass in 2023 was the first known instance of orca predation of the species in Australian waters. "These findings provide compelling evidence of killer whale predation on white sharks in Australian waters, with a strong indication of selective liver consumption," Reeves says. "This suggests that such predation events may be more widespread and prevalent across the globe than previously believed." Two days before the carcass washed ashore, near Portland in the Australian state of Victoria, two locally known orcas named Bent Tip and Ripple were seen hunting, and catching, large prey in nearby Bridgewater Bay. This may have been the hunt in question, although confirmation would be difficult to obtain. All we know for now is that the culprit was orcas – but that's quite mind-blowing. Orcas have their own habitats, hunting grounds, and specialties. Different groups in different locations don't intermingle, communicate, or breed with each other. It raises some interesting questions about how similar hunting behavior could have emerged in two very different locations. It's possible that orca predation of white sharks is just a more widespread, normal behavior than we knew about. If this is the case, we need to learn more about it and how it affects the rest of the ecosystem. The displacement of a top predator can have grave effects: in South Africa, for instance, reduced shark presence means a drop in shark predation on elephant seals, which could increase food competition for the seals later. If orcas in Australian waters have started preying on white sharks, that could have implications for populations of the animals sharks normally eat. "Evidence suggests that the white sharks being displaced or directly killed as a result of the killer whale predation in South Africa has led to cascading shifts in the wider marine ecosystem," says ecological geneticist Adam Miller of Flinders University. "We know that white sharks are key regulators of ecosystem structure and functions, so it's very important we preserve these top predators. Therefore, it is important that we keep a tab on these types of interactions in Australian waters where possible." The research has been published in Ecology & Evolution. 'Beyond Doubt': Proteins in Fossil From Actual Dinosaur, Claim Scientists 'Lost City' Deep Under The Ocean Is Unlike Anything We've Ever Seen Before on Earth Octopuses May Have The Oldest Sex Chromosomes in The Animal Kingdom
