Dolphins learn to wear sponges ‘like a clown nose' to hunt fish
These bottlenose dolphins don a sponge on their beak, akin to a clone nose, allowing them to safely shovel through rocky seabed channels. This method stirs up barred sandperch, making them an easy meal.
However, new research published in the journal Royal Society Open Science reveals this inherited behaviour is more challenging than it appears.
The sponge, while protective, interferes with the dolphins' sophisticated echolocation system, their primary means of navigation and sensing through sound.
'It has a muffling effect in the way that a mask might,' said co-author Ellen Rose Jacobs, a marine biologist at the University of Aarhus in Denmark. 'Everything looks a little bit weird, but you can still learn how to compensate."
Jacobs used an underwater microphone to confirm that the 'sponging' dolphins in Shark Bay, Australia, were still using echolocation clicks to guide them. Then she modelled the extent of the sound wave distortion from the sponges.
For those wild dolphins that have mastered foraging with nose sponges, scientists say it's a very efficient way to catch fish. The wild marine sponges vary from the size of a softball to a cantaloupe.
Sponge hunting is 'like hunting when you're blindfolded — you've got to be very good, very well-trained to pull it off," said Mauricio Cantor, a marine biologist at Oregon State University, who was not involved in the study.
That difficulty may explain why it's rare — with only about 5% of the dolphin population studied by the researchers in Shark Bay doing it. That's about 30 dolphins total, said Jacobs.
'It takes them many years to learn this special hunting skill — not everybody sticks with it,' said marine ecologist Boris Worm at Dalhousie University in Canada, who was not involved in the study.
Dolphin calves usually spend around three or four years with their mothers, observing and learning crucial life skills.
The delicate art of sponge hunting is 'only ever passed down from mother to offspring,' said co-author and Georgetown marine biologist Janet Mann.
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The Associated Press Health and Science Department receives support from the Howard Hughes Medical Institute's Science and Educational Media Group and the Robert Wood Johnson Foundation. The AP is solely responsible for all content.
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The Guardian
10 hours ago
- The Guardian
Dr Karl Kruszelnicki: ‘I took my hands off the artery – blood squirted up and hit the ceiling'
You're about to give a series of talks on the history and explosion of AI. Who is your favourite fictional robot? I guess the robots in general from Isaac Asimov. He came up with the three laws of robotics, which are basically that a robot has to obey a human, it can't harm itself, and it can't harm another human. My favourite robot is one [from Asimov's The Bicentennial Man] that served a family for many, many years – in fact, generations – and eventually became human. If you could change the size of any animal to keep as a pet, what would it be? To put a downer on it, we're full of children and nieces and nephews and grandkids, so we don't want pets. But I do see the value of a pet. It's tricky. In Australia, cats kill a million birds a day. Dogs are nice, but when I was a doctor in a kids hospital, once I realised that dogs would rip the faces off 15,000 kids every year, I kind of fell out of love with big dogs. So I reckon dogs. Shrink them down. A border collie, they're the smartest dog. What do you do when you can't get to sleep? Get up, work for a bit, then go to sleep again when I feel tired. If I'm awake enough to do stuff, I'll do stuff. I love reading. My job is to read the scientific literature and turn it into stuff that people can understand. I've been reading articles about how we've got this history of human diseases over the last 37,000 years, and how many diseases have actually invaded our DNA, or how some frogs will fake death to avoid sex, or how the French in the early 1800s had the great moustache wars, or the TV viewing habits of dogs. Or the word 'cool' – where did it come from, and what's the concept behind it? Or the amount of energy used from AI to make a single picture, as opposed to a human, or why you get traffic jams in the middle of nowhere, or how you use earwax as a diagnostic tool. Or, if you get a shark and turn it upside down, about half the species will just stop moving. And that's just today's reading! What is your most controversial scientific opinion? The two big ones would have to be climate change and vaccination, and the controversy behind them is just pointless. You know how insurance companies are making it more expensive in certain areas to insure because of extreme events caused by climate change? OK, so when do you think the insurance companies started doing that? 1973! [It wasn't until 1980 that] fossil fuel companies, with a budget of up to a billion dollars a year, started denying climate change. And that's why I've got this so-called controversy. What is the oldest thing you own, and why do you still have it? I've got a bit of rock from a mining site that was dated to 1bn years old. I've also a meteor that my father saw land in our front garden when I was a kid, and the next morning, we went out to dig it up. I reckon that'd be a couple of billion years old. It's about the size of a golf ball. It's now on the display shelf halfway up the stairs. Would you rather die at the bottom of the ocean or out in space? Probably space. But it depends how it happens. One thing I learned as a medical doctor is that everybody has to die, but you should have a good death. We had one patient who had cancer of the everything, and she was really going to die. We made it our personal project that she'd have a good death. We ended up cranking her morphine from 5mg a day to 30,000 – that's a big jump, isn't it? Her legs were the diameter of your wrist by the time she died, but she didn't die in pain. So that convinced me, I want to have a good death. Sign up for the fun stuff with our rundown of must-reads, pop culture and tips for the weekend, every Saturday morning If you're in, say, a submarine, and then the pressure overcomes the structural integrity of the vessel's walls, then you're dead in about a tenth of a second, a hundredth of a second – whereas in space, it might take a while to die, maybe a few minutes. So whichever one was quicker. But the view's nicer in space. What is the strangest job you've ever had? I started working at the steelworks at Wollongong when I was about 19. I ran a little aluminium boat measuring the acidity or alkalinity of the water in this little creek inside the steelworks. Depending on whether it was green or orange, it varied between incredibly acid and incredibly alkaline. And either way, it would eat through the skin of the aluminium boat in about six months. 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The reason we have seven colours in our rainbow is because of Isaac Newton. Besides being one of the true geniuses, he also spent more time on Bible studies than he did on science. And all the way through the Bible the number seven comes up all the time. Based on him following the work of some Muslim scientists, he did an experiment with a prism – like the Dark Side of Moon album cover, which, by the way, is wrong from a physics point of view. Anyway, he sees these colours. Six colours. But he loves the Bible, and the Bible has seven everywhere, so he sticks in stupid fucking indigo. What sort of colour is indigo? It's just blue! So I refuse to add another colour to the rainbow. I'll go the other way; I'll remove indigo and get back to six colours. Lastly, please settle this debate for us once and for all, scientifically: should tomato sauce be kept in the fridge or the cupboard? The problem that you want to avoid is bacterial or fungal infection of the tomato sauce. 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The Guardian
a day ago
- The Guardian
How to reduce your food footprint: if it's better for you, it's better for the planet
Food production globally accounts for nearly 30% of greenhouse gas emissions, with the average Australian diet contributing more than 3kg of Co2 per person per day. And what's worse, we waste about 35% of the food we bring home. If we keep this up, it has been estimated the already unsustainable environmental cost of the food system will nearly double by 2050. Calculating the precise impact your individual food choices have on the environment isn't simple, but research suggests the actions we can take to bring that impact down are – and they aren't just better for the environment, they're better for our health too. A 2021 CSIRO study found that sticking to its healthy eating guidelines while choosing lower-carbon options could reduce the climate impact of our diets by as much as 42%. Another released last year, which conducted life-cycle assessments on more than 60 thousand products available on Australian shelves, found that switching to lower-emission options within similar categories could bring our food footprints down by an impressive 71%. Prof Simone Pettigrew, program director of food policy at the George Institute for Global Health and an author of the latter study, says: 'There's four biggies that sit at the top of the list for being the least sustainable: traditional red meats, dairy products, and then to a lesser extent – but perhaps more upsettingly – coffee and chocolate.' Consumers, she says, can make a 'massive, massive difference' to the sustainability of their entire food basket simply by limiting or switching out those items. In practical terms this might look like choosing poultry, seafood or kangaroo instead of lamb or pork, switching dairy milk for plant-based options, drinking just one less coffee a day or choosing sweet treats with low or no cocoa content. Even if we can do that some of the time, the difference can be significant, according to Pettigrew. When it comes to carbohydrates and fresh produce, Pettigrew says a solid rule of thumb is the better it is for you, the better it probably is for the planet. Choosing fresh fruits and vegetables to snack on rather than processed biscuits or bars, for example, will dramatically reduce your diet's carbon footprint. And while there are production and processing differences between more nutritionally similar items such as pasta and rice, Pettigrew says overall they are largely comparable in terms of sustainability. 'Anything that is plant based is going to be much less environmentally costly than anything animal based. 'We understand it's hard for consumers to make really big changes in one hit, but it is relatively easy to make small incremental ones.' If you already eat a healthy, plant-rich diet, limit your ultra-processed food intake and are keeping your coffee and chocolate habits in check, you've made a great start. Beyond that, Dr Lilly Lim-Camacho, principal research scientist with CSIRO Agriculture and Food, says one of the most helpful things consumers can do to maximise these gains is to 'shop with intent'. Food waste accounts for more than a third of all household waste, so only purchasing what you need combined with small efforts such as 'learning how to use up leftover veggies in the crisper' and resisting impulse buying will not only make your diet significantly more sustainable, but healthier and more economical too. She urges people to also keep in mind that wasting unhealthy food is doubly bad. 'Not only do discretionary foods create more emissions, our bodies don't actually need them.' Those emissions are essentially being wasted regardless of whether you consume the food or not, she suggests. If you'd like to take things a step further, apps such as ecoSwitch, developed by the George Institute, get into the nitty gritty of comparing the carbon ratings associated with more specific items. This can help if you want to know, for example, which brand of tinned tomatoes or tofu is best. The George Institute study found that opting for near identical but lower-impact options alone could bring your food footprint down by 26%. Neither Pettigrew nor Lim-Camacho want to take the fun out of food or expect consumers to forgo the odd burger or chocolate ice-cream, but agree that by prioritising our health we will naturally make better choices for the planet, and vice versa. 'It's a win-win,' says Pettigrew. 'There is always going to be an environmental cost to our food. But it's important for people to know that you actually can make an enormous difference if you want to.'
The Guardian
a day ago
- The Guardian
Can a common denominator unite warring contestant nations at the International Mathematics Olympiad?
A resounding cheer erupted when on Monday three Palestinian teenagers shuffled on to the stage of a convention centre tucked away behind the golden beaches of Australia's Sunshine Coast. All of them from the West Bank, they were only half of a team able to attend the International Mathematics Olympiad, a gathering of the world's brightest young mathematical minds, where medals can offer tickets to any university in the world and launch brilliant careers. Two of their compatriots from war-ravaged Gaza could not make the journey to Australia and would instead attempt to compete remotely. But this was a marked improvement from last year's event in England, for which no Palestinian could secure a visa in time. Yet this heartfelt moment at the 66th IMO opening ceremony was followed by one that hinted at the deep divisions – driven by geopolitics and global conflict – which had played out behind closed doors just the day before and which threatened to unravel the oldest and most prestigious competition of young mathematicians. Sign up for Guardian Australia's breaking news email The students in the room did not know it, but a jury of delegates from the 114 nations gathered had, the day prior, voted as of the conclusion of the event to lift a suspension applied to Russia's membership after its 2022 full-scale invasion of Ukraine. The Ukrainian leaders were distraught, the Estonians and other Baltic nations among the outraged. Their talk had already turned to boycott. Even in the midst of Russia's full-scale invasion, Ukraine boasts an astonishing mathematical achievement. The year the war began, in 2022, Russia was suspended from the IMO and Ukrainian IMO students were evacuated. One among them from war-torn Kharkiv, Ihor Pylaiev, won his second gold medal – with a perfect score and a joint top-ranked position in the world. A number of his compatriots also medalled and, after this achievement, would earn scholarships at Cambridge. Kyiv was supposed to host last year's maths olympiad. IMO Ukraine team leader Bogdan Rublev said in his country, 'the IMO is a very important event'. Even as war raged, the Ukrainians remained optimistic that the violence would end and they could host the IMO as planned. But, those hopes were officially dashed when Bath was named Kyiv's replacement. 'It broke our hearts,' Rublev said. 'We had worked hard to prepare and we were excited to welcome the world to our country.' Fellow Ukrainian representative Anastasiia Venchkovska, who was translating for Rublev on the Sunshine Coast, said Russia's IMO suspension was 'not just about mathematics'. 'Russia is not just a country at war, it is a state that systemically targets education, culture and children,' Venchkovska said. 'That is terrorism.' 'A country that destroys Ukrainian schools and universities should not sit at the same table as those against whom it commits genocide every day.' The opening ceremony at the Twin Waters Novotel Resort on Monday was well intentioned and, otherwise, good fun. The parade of nations, each with teams of up to six high school students, was determined by the distance each had travelled to compete. In a room full of sharp minds, it was a bit of sport to guess at the order by which teams would take to the stage and pose for the cameras. The Moroccans (17,934km) surprised many by being called up first, each in flowing white robes beneath a red fez, before making way for the Portuguese (17,887km), who bounded and hooted up the stairs to form a mini-pyramid. The Norwegians (15,333km) wore black suits, ties and sunglasses inside, the Peruvians (13,117km) football-style red and white trackies. The Iraqis (13,240km) chanted 'Lions of Mesopotamia!', the Aussies (1,030km) 'Oi, Oi, Oi!' The three young Palestinians (14,044km), however, made no spectacle, each briefly clutching their national flag. Their faces betrayed little emotion. They didn't have to – everyone in the room understood how much it meant to stand on that stage, knew the life-changing opportunity that platform might provide. 'It was very beautiful,' Palestine team leader Samed AlHajajla said. 'The happiness is not complete, it was sad that we couldn't have all the children.' 'But at least it is good to have half of the team here in person.' Though few picked who would open the parade, it didn't take a genius to guess who would follow the Palestinians. Six young Israelis (14,040km) came smiling on stage, playfully brandishing soft toy otters, the team's mascot, and two Star of David flags. The cheers and applause fell to a smatter. One or two muttered boos. Had an effort to suspend Israel's IMO membership on Sunday been successful, this moment might never have transpired. These six young people could still have competed – but remotely. The Israeli flag, like the Russian, would not have flown on the Sunshine Coast, nor next year at Shanghai. Instead, the opposite will happen. Sign up to Breaking News Australia Get the most important news as it breaks after newsletter promotion The IMO is a tightly choreographed and controlled event: team leaders set the exam questions and so have to be quarantined from their students to prevent cheating. Before being whisked away to the leaders' site at a resort in Noosa, IMO board president Gregor Dolinar briefly answered questions about the jury meeting which resolved to lift Russia's suspension. He described it as a 'long and constructive' discussion from which the main message was that 'we want to stay out of politics as much as possible'. 'We exchanged our views and we said that our primary goal is to enable as many kids from all around the world to come to the same place and to give them this opportunity to show their talent,' Dolinar said. 'So mathematics is our primary goal – if we will start to be involved in politics, we do not know where to draw the line'. The jury meeting began with AlHajajla and lasted several hours. The Palestinian team leader spoke with passion about the ordeal of his country's representatives, in particular those trapped amid the horrors of Gaza. Other nations, particularly those from the global south, agreed and spoke in support of the Palestinian motion to suspend Israel. Dolinar made several arguments as to why the IMO should remain, nonpolitical. Among them was that being political was bad for business. The sponsors that the non-profit organisation needed to finance such a logistically complicated event, he warned, did not want to deal with politically motivated organisations. The IMO board put forward its own motion which proposed that measures only be taken against a member for breaking IMO regulations – for widespread cheating, say. All current suspensions – only Russia – would expire at the end of the Australian event. This caught many by surprise – restoring Russia's membership was not in the agenda. But the motion passed with a secret ballot of 62 in favour to 23 against, with six abstentions. Israeli team leader Dan Carmon said it was 'the right choice for the IMO at this time', adding that the organisation – which is run by volunteers – spent a lot of time in the lead up to the event discussing its stance on political matters. 'I think it will be much better for the IMO, and the fostering of young minds everywhere, that we are now focusing on inclusivity instead of excluding students and countries,' Carmon said. 'I think that is a much better direction for the IMO to go in order to promote the love of mathematics in the world and promote brotherhood between nations.' Far from brotherhood – for Rublev, Venchkovska and the Ukrainians – even sharing a stage with the Russian flag was 'impossible and unacceptable'. 'We came here not only to compete but to remind the world that, behind every problem we solve on paper, there is a much bigger problem we are living through in reality,' they said. 'We ask the international community to stay consistent, to stay principled and to stand with Ukraine'. Estonian team leader Oleg Košik said his was among the Baltic nations who made clear in 2022 that they would do so 'We see the continuous barbaric aggression of Russia against Ukraine,' Košik said. 'The constant bombings of cities, innocent civilians being killed every night. If the IMO will say now, 'OK, this is fine, we don't care about it' – what message does it send to the whole world?'
