Latest news with #UniversitéPSL
Euronews
26-04-2025
- Science
- Euronews
Some shark bites are ‘survival instinct', researchers say in defence of threatened predator
ADVERTISEMENT 'It's more scared of you than you are of it' is a refrain parents use to humanise spiders to their children. That's a little harder to believe of sharks, given their mighty appearance and characterisation in the media. But researchers have found that - like snakes and spiders - sharks do sometimes bite humans in self-defence. "We show that defensive bites by sharks on humans - a reaction to initial human aggression - are a reality and that the animal should not be considered responsible or at fault when they occur," says Dr Eric Clua, first author of the new study published in the Frontiers in Conservation Science journal. "These bites are simply a manifestation of survival instinct, and the responsibility for the incident needs to be reversed,' according to Clua, a shark specialist and researcher at Université PSL in Paris. Related Shark and ray populations have halved since 1970 and overfishing is to blame More than 80% of the world's coral reefs hit by worst bleaching event in recorded history What makes a shark bite in self-defence? Firstly, shark attacks are rare, occurring only 100 or so times a year. Just around 10 per cent are fatal; statistically , you are more likely to die in a lawn mower accident. To understand more about shark bite motivations, which are already known to range from competition to predation, the researchers focused on the territorial waters of French Polynesia. This 5.5 million square kilometre zone is home to more than 30 shark species, and has been a designated shark sanctuary since 2006, making it an ideal place to study shark behaviour. The team used shark bite data collected systematically over the past 60 years in French Polynesia to identify self-defence bites on humans. They looked for incidents where sharks bit in response to aggressive human actions, such as spear fishing or attempts to grab the shark. In contrast to 'feeding-motivated' bites, sharks acting in self-defence generally bite repeatedly and leave superficial, non-lethal wounds. This lower-grade violence matches the kind of defence-motivated bites inflicted by land predators like bears and large birds such as cassowaries, the researchers note. Related What are milky seas? 400 years of sailors' stories are shedding light on ocean bioluminescence How common are self-defence shark bites? Between 2009 and 2023, 74 bites were documented in French Polynesia. Four of them were likely motivated by self-defence, the study found, which may trigger 3 to 5 per cent of all shark bites. Collecting this data on a global scale is tricky, but the researchers made a start by applying their approach to the Global Shark Attack Files, which records almost 7,000 bites since 1863. This database categorises bites as 'provoked' or 'unprovoked'. The researchers focused on the former, and bites linked to activities that might put people in proximity to sharks. They found that 322 bite events could have been motivated by self-defence, a figure close to the percentage (around 5 per cent) of self-defence bites recorded in French Polynesia. "We need to consider the not very intuitive idea that sharks are very cautious towards humans and are generally afraid of them," Clua says. ADVERTISEMENT When sharks strike in self-defence, they might use disproportionate force and deliver greater harm than is threatened (not unlike humans). "The sharks' disproportionate reaction is probably the immediate mobilisation of their survival instinct,' adds Clua. 'It is highly improbable that they would integrate revenge into their behaviour and remain above all pragmatic about their survival." Related The climate crisis may cause more whale shark collisions with ships - here's why How can you avoid being bitten by a shark? To avoid being bitten by a defensive shark, people should steer clear of any activity that could be considered aggressive, the researchers advise. This includes attempts to help stranded sharks, which are liable to be misinterpreted by the big fish. "Do not interact physically with a shark, even if it appears harmless or is in distress. It may at any moment consider this to be an aggression and react accordingly," Clua cautions. ADVERTISEMENT "These are potentially dangerous animals , and not touching them is not only wise, but also a sign of the respect we owe them." Knowing your coastal sharks is important, too. For some species, such as the territorial-minded gray reef shark, a human merely intruding into their space is likely to trigger their survival instinct. Related Toxic dust and stressed seals: What the shrinking Caspian Sea could mean for people and nature Reviewing our view of shark attacks 'The existence of self-defence bites … calls into question the practice of labelling all shark bites as attacks,' the researchers conclude. The media plays a key role in this perception, tending to portray sharks as the aggressor even when people initiate the interaction. In April 2016, for example, reports on a bite incident involving two Polynesian fishermen who were aggressive a gray reef shark all had the word 'attack' in the headlines. ADVERTISEMENT 'This simplistic approach damages the image of sharks and, indeed, their conservation, which relies on public support,' the researchers add. With 'negative interactions' between humans and sharks on the rise due to our increased use of the sea, they hope their study will feed into a more sustainable style of wildlife management. As in other areas of the animal kingdom, a better understanding of what motivates endangered species to attack people can help develop non-lethal strategies.
Yahoo
25-04-2025
- Science
- Yahoo
Some shark bites are ‘survival instinct', researchers say in defence of threatened predator
'It's more scared of you than you are of it' is a refrain parents use to humanise spiders to their children. That's a little harder to believe of sharks, given their mighty appearance and characterisation in the media. But researchers have found that - like snakes and spiders - sharks do sometimes bite humans in self-defence. "We show that defensive bites by sharks on humans - a reaction to initial human aggression - are a reality and that the animal should not be considered responsible or at fault when they occur," says Dr Eric Clua, first author of the new study published in the Frontiers in Conservation Science journal. "These bites are simply a manifestation of survival instinct, and the responsibility for the incident needs to be reversed,' according to Clua, a shark specialist and researcher at Université PSL in Paris. Related Shark and ray populations have halved since 1970 and overfishing is to blame More than 80% of the world's coral reefs hit by worst bleaching event in recorded history Firstly, shark attacks are rare, occurring only 100 or so times a year. Just around 10 per cent are fatal; statistically, you are more likely to die in a lawn mower accident. To understand more about shark bite motivations, which are already known to range from competition to predation, the researchers focused on the territorial waters of French Polynesia. This 5.5 million square kilometre zone is home to more than 30 shark species, and has been a designated shark sanctuary since 2006, making it an ideal place to study shark behaviour. The team used shark bite data collected systematically over the past 60 years in French Polynesia to identify self-defence bites on humans. They looked for incidents where sharks bit in response to aggressive human actions, such as spear fishing or attempts to grab the shark. In contrast to 'feeding-motivated' bites, sharks acting in self-defence generally bite repeatedly and leave superficial, non-lethal wounds. This lower-grade violence matches the kind of defence-motivated bites inflicted by land predators like bears and large birds such as cassowaries, the researchers note. Related What are milky seas? 400 years of sailors' stories are shedding light on ocean bioluminescence Between 2009 and 2023, 74 bites were documented in French Polynesia. Four of them were likely motivated by self-defence, the study found, which may trigger 3 to 5 per cent of all shark bites. Collecting this data on a global scale is tricky, but the researchers made a start by applying their approach to the Global Shark Attack Files, which records almost 7,000 bites since 1863. This database categorises bites as 'provoked' or 'unprovoked'. The researchers focused on the former, and bites linked to activities that might put people in proximity to sharks. They found that 322 bite events could have been motivated by self-defence, a figure close to the percentage (around 5 per cent) of self-defence bites recorded in French Polynesia. "We need to consider the not very intuitive idea that sharks are very cautious towards humans and are generally afraid of them," Clua says. When sharks strike in self-defence, they might use disproportionate force and deliver greater harm than is threatened (not unlike humans). "The sharks' disproportionate reaction is probably the immediate mobilisation of their survival instinct,' adds Clua. 'It is highly improbable that they would integrate revenge into their behaviour and remain above all pragmatic about their survival." Related The climate crisis may cause more whale shark collisions with ships - here's why To avoid being bitten by a defensive shark, people should steer clear of any activity that could be considered aggressive, the researchers advise. This includes attempts to help stranded sharks, which are liable to be misinterpreted by the big fish. "Do not interact physically with a shark, even if it appears harmless or is in distress. It may at any moment consider this to be an aggression and react accordingly," Clua cautions. "These are potentially dangerous animals, and not touching them is not only wise, but also a sign of the respect we owe them." Knowing your coastal sharks is important, too. For some species, such as the territorial-minded gray reef shark, a human merely intruding into their space is likely to trigger their survival instinct. Related Toxic dust and stressed seals: What the shrinking Caspian Sea could mean for people and nature 'The existence of self-defence bites … calls into question the practice of labelling all shark bites as attacks,' the researchers conclude. The media plays a key role in this perception, tending to portray sharks as the aggressor even when people initiate the interaction. In April 2016, for example, reports on a bite incident involving two Polynesian fishermen who were aggressive a gray reef shark all had the word 'attack' in the headlines. 'This simplistic approach damages the image of sharks and, indeed, their conservation, which relies on public support,' the researchers add. With 'negative interactions' between humans and sharks on the rise due to our increased use of the sea, they hope their study will feed into a more sustainable style of wildlife management. As in other areas of the animal kingdom, a better understanding of what motivates endangered species to attack people can help develop non-lethal strategies.
Daily Mail
25-04-2025
- Science
- Daily Mail
Scientists reveal best way to avoid a shark attack
Since the release of Jaws in 1975, many people have been terrified of sharks. Scientists have revealed the best way to avoid a shark attack. Despite their fearsome reputation, there are only around 100 shark bites per year - roughly 10 per cent of which are fatal. Sharks may bite for a multitude of reasons, ranging from competition and being territorial to predation. Now, an international team of researchers found that there might be an additional, little-discussed motivator causing sharks to bite. It might sound unlikely, but the animals may also bite due to self-defense, experts say. So, while it might sound obvious, if you want to avoid a shark attack, simply leave sharks alone - even if they look like they're in distress. Dr Eric Clua, a shark specialist and researcher at Université PSL, said: 'We show that defensive bites by sharks on humans - a reaction to initial human aggression - are a reality and that the animal should not be considered responsible or at fault when they occur. 'These bites are simply a manifestation of survival instinct, and the responsibility for the incident needs to be reversed.' He said that self-defense bites are in response to human action that is, or perceived to be, aggressive. This can include during obvious activities such as spear fishing - but a human merely intruding their space could be enough. 'Do not interact physically with a shark, even if it appears harmless or is in distress,' Dr Clua said. 'It may at any moment consider this to be an aggression and react accordingly. 'These are potentially dangerous animals, and not touching them is not only wise, but also a sign of the respect we owe them.' Some species of coastal shark, such as the grey reef shark, are both particularly territorial and bold enough to come into contact with humans. When sharks strike in self-defense, they might use disproportionate force and may deliver greater harm than is threatened, he explained. 'We need to consider the not very intuitive idea that sharks are very cautious towards humans and are generally afraid of them,' he said. 'The sharks' disproportionate reaction probably is the immediate mobilization of their survival instinct. 'It is highly improbable that they would integrate revenge into their behaviour and remain above all pragmatic about their survival.' Figures show that in 2024, just 47 people were hurt in unprovoked shark attacks – the lowest level in almost 30 years. This included four deaths, during a year experts deemed 'an exceptionally calm year for shark bites'. The majority of these bites happened in the U.S., with 28 attacks recorded across six states. Half of the country's shark attacks happened in Florida, where the long coastline and warm water make it more likely people and sharks will come into contact. Elsewhere, Australia recorded nine shark bites, while 10 other territories recorded one bite each. Meanwhile, in the average year, humans kill tens of millions of sharks.
Daily Mail
25-04-2025
- Science
- Daily Mail
Scientists reveal how to avoid a shark attack - and their method is surprisingly simple
Since the release of Jaws in 1975, many people have been absolutely terrified of sharks. Now, scientists have worked out the main reason behind some of their attacks. And their discovery could prove valuable advice for anyone thinking of getting in the sea. Despite their fearsome reputation, there are only around 100 shark bites per year - roughly 10 per cent of which are fatal. Sharks may bite for a multitude of reasons, ranging from competition and territorialism to predation. Now, an international team of researchers found that there might be an additional, little-discussed motivator causing sharks to bite. It might sound unlikely, but the animals may also bite due to self-defence, experts say. So, while it might sound obvious, if you want to avoid a shark attack, simply leave sharks alone - even if they look like they're in distress. Dr Eric Clua, a shark specialist and researcher at Université PSL, said: 'We show that defensive bites by sharks on humans – a reaction to initial human aggression – are a reality and that the animal should not be considered responsible or at fault when they occur. 'These bites are simply a manifestation of survival instinct, and the responsibility for the incident needs to be reversed.' He said that self-defense bites are in response to human action that is, or perceived to be, aggressive. This can include during obvious activities such as spear fishing – but a human merely intruding their space could be enough. 'Do not interact physically with a shark, even if it appears harmless or is in distress,' Dr Clua said. 'It may at any moment consider this to be an aggression and react accordingly. 'These are potentially dangerous animals, and not touching them is not only wise, but also a sign of the respect we owe them.' Some species of coastal shark, such as the grey reef shark, are both particularly territorial and bold enough to come into contact with humans. Shark fins are pictured as they swim the Mediterranean sea waters off the coast of Hadera in central Israel on April 22, 2025. Remains have been found after a man went missing following a suspected shark attack How to avoid a shark attack The best way to avoid being bitten is to steer clear of any activity that could be considered an aggression. This includes trying to help stranded sharks, as attempts to help will not necessarily be perceived as such. 'Do not interact physically with a shark, even if it appears harmless or is in distress. It may at any moment consider this to be an aggression and react accordingly,' Dr Clua cautioned. 'These are potentially dangerous animals, and not touching them is not only wise, but also a sign of the respect we owe them.' When sharks strike in self-defence, they might use disproportionate force and may deliver greater harm than is threatened, he explained. 'We need to consider the not very intuitive idea that sharks are very cautious towards humans and are generally afraid of them,' he said. 'The sharks' disproportionate reaction probably is the immediate mobilization of their survival instinct. 'It is highly improbable that they would integrate revenge into their behaviour and remain above all pragmatic about their survival.' His research has focused on shark bites in French Polynesia, where they have been recorded since the early 1940s. Records including reliable information about bite motivation, however, begin later. Between 2009 and 2023, 74 bites were documented, four of them likely motivated by self-defense, which may trigger 3 to 5 per cent of all shark bites. They said their findings might be transferable to shark bites in the rest of the world. The findings were published in the journal Frontiers in Conservation Science. Figures show that in 2024, just 47 people were hurt in unprovoked shark attacks – the lowest level in almost 30 years. This included four deaths, during a year experts deemed 'an exceptionally calm year for shark bites'. The majority of these bites happened in the USA, with 28 attacks recorded across six states. Half of the country's shark attacks happened in Florida, where the long coastline and warm water make it more likely people and sharks will come into contact. Elsewhere, Australia recorded nine shark bites, while 10 other territories recorded one bite each. Meanwhile, in the average year, humans kill tens of millions of sharks. Commenting on the figures at the time Dr Diego Vaz, Senior Curator of Fishes at the Natural History Museum, said: 'Millions of sharks are killed each year, from newborns through to fully grown adults, and we're also destroying their environment. 'In comparison, 47 people being bitten seems so small, especially across so many kilometres of beach around the world. 'We need to remind ourselves that we're entering their environment as visitors, and so we need accept the risks that brings and take precautions where needed. 'Sharks have been on Earth for over 400 million years, much longer than humans, so we're the ones who are invading their space.' HOW SHARKS EARNED THEIR RUTHLESS REPUTATION Sharks are the most efficient predators on earth and have long terrified humans. Their basic design has never really changed over the course of 200million years and they are considered to be complex and intelligent. Their teeth are fear factor number one, with the great white's teeth growing up to two-and-a-half inches in length. Their prey are impaled on the pointed teeth of the lower jaw where they saw away sections of the flesh. The serrated edges of the teeth help with this process. Their teeth are brittle and are constantly breaking off but are also constantly regrowing and on average there are 15 rows of teeth present in the mouth at one time. Their speed is fear factor number two. They are very fast in the water compared to humans with the mako shark able to reach an incredible 60mph in bursts. The great white can reach speeds of 25mph. By comparison, 5mph is the fastest a human being can reach. A shark's power and size terrifies us, too. The great white shark can grow up to 20 feet and while it has no particular taste for humans even an exploratory bite is enough to cut a man in half. Most sharks release a human after its first bite but sometimes, that's all it take to kill a person. However, sharks have far more reason to be afraid of humans. We kill up to a million of them a year, often just cutting off their fins to make into soup and throwing the rest of the shark back into the water, where it starves or drowns.
