Killer whales and dolphins have been working together to hunt salmon in the northern Pacific Ocean, an unexpected finding that further reveals the complex social lives of marine mammals.

Video cameras and sensors attached to nine killer whales 鈥� also known as orcas 鈥� showed four of them diving with numerous Pacific white-sided dolphins towards Chinook salmon hiding in the depths off northern Vancouver Island. Three more whales were observed by drone. The orcas ate the salmon, while the dolphins scavenged the scraps.

鈥淭hey were cooperatively foraging,鈥� says at Dalhousie University in Canada. 鈥淵ou could anthropomorphise it and say that they鈥檙e being friends for hunting purposes.鈥�

Also known as king salmon, Chinook salmon can grow more than a metre long and are often too big for dolphins to eat.

But northern Vancouver Island whales are messy eaters and often tear fish apart to share with family, leaving blood, scales and fragments for dolphins to consume. The dolphins help whales 鈥渟cout鈥� out salmon, the researchers believe.

Six out of the 12 whales interacted with the dolphins, orienting to face them a combined total of 102 times in the videos. Four dived with dolphins as deep as 60 metres, where it鈥檚 dark and salmon can take cover among rocks and crevasses.

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While both species emitted clicks and buzzes, the sensor data revealed that whales often reduced their echolocation 鈥� apparently to 鈥渆avesdrop鈥� on the dolphins. Since echolocation is narrowly focused like a spotlight, a large number of dolphins scanning the water may improve a whale鈥檚 chances of finding fish, says Fortune.

鈥淚t鈥檚 like turning on the high beams鈥� on a car, she says, 鈥渁nd the light is the sound.鈥�

女生小视频s have previously found inter-species cooperation such as fish leading an octopus toward crustaceans, or honeyguide birds leading a human to bee colonies. But killer whales鈥� scientifically observed interactions with other species have typically been to prey on or harass them.

Orcas around the Iberian peninsula have recently rammed and sunk half a dozen sailboats, although scientists say it鈥檚 more likely than attacking them.

at Ocean Wise, a global conservation organisation, argues dolphins in the study are stealing scraps rather than cooperating with whales. In a she and her colleague published this year, drone footage in the same area showed whales appearing to ignore, play with or, in one case, lunge at dolphins. Her study concluded dolphins were mainly seeking protection from a particular population of mammal-eating orcas known as Biggs鈥� killer whales, which avoid the resident killer whales.

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鈥淲e observed no clear evidence of benefits to the killer whales,鈥� says Visona-Kelly.

last month reported 30 to 40 Pacific white-sided dolphins circling an emaciated killer whale known to researchers as I76, who dived and didn鈥檛 re-emerge. This suggested the dolphins may have 鈥渆xhausted I76 so that he was unable to return to the surface鈥�, according to the paper.

at the University of St Andrews, UK, says the new research convincingly shows cooperation, regardless of whether the whales could interpret dolphin echolocation or were simply attracted to the commotion as a possible sign of fish.

鈥淭hese animals are smart and behaviourally flexible,鈥� he says. 鈥淲e鈥檒l see all kinds of interactions between killer whales and dolphins, everything from the killer whales eating them to playing with them to cooperating with them.鈥�

Orcas in the Gulf of California have been hunting juvenile great white sharks using a clever tactic: flipping them upside down to render them immobile. The discovery suggests there may be a previously unrecognised group of orcas in the region that specialises in hunting sharks.

Only a few orca populations are known to , and even fewer have been found to eat great whites (Carcharodon carcharias). For example, orcas (Orcinus orca) off the coast of San Francisco were , and a great white carcass near Australia showed signs of an orca attack in . But until recently, there had only been one known instance, recorded in South Africa, of the animals preying on juvenile great white sharks.

, an independent marine biologist in Mexico, and his colleagues captured video footage of orcas in the Gulf of California hunting juvenile great white sharks on two separate occasions. The first, recorded in August 2020, showed five female orcas working together to push a young great white to the surface. 鈥淭he orcas were ramming the great white to flip it upside down,鈥� says Higuera.

The manoeuvre forced the shark into a state of temporary paralysis, called tonic immobility. It also allowed the orcas to get at the shark鈥檚 energy-rich liver, which they shared amongst themselves. A few minutes later, the pod repeated the attack on a different adolescent great white. In August 2022, the research team recorded another group of five orcas using the same technique to hunt a young great white around the same location at the same time of year.

The researchers identified some of the orcas in the first incident as those previously spotted hunting whale sharks and bull sharks. Footage from the second incident wasn鈥檛 clear enough to determine whether these orcas belonged to the same pod. 鈥淏ut it is highly possible,鈥� says Higuera.

Orca populations drastically differ depending on where they are located. 鈥淥rcas are hunting machines. They are like snipers 鈥� they use specific hunting strategies, very specific ones depending on their prey,鈥� says Higuera. These findings suggest the orcas belong to a previously unrecognised shark-eating group, he says.

鈥淪o now we have an example of another unique feeding strategy that probably isn鈥檛 shared by any other group of [orcas] in the world,鈥� says at the University of British Columbia in Canada. However, more research is needed to know for sure, as the orcas could be an offshoot of those from the Pacific Northwest that hunt other types of sharks, he says.

Humpback whale songs have statistical patterns in their structure that are remarkably similar to those seen in human language. While this doesn鈥檛 mean the songs convey complex meanings like our sentences do, it hints that whales may learn their songs in a similar way to how human infants start to understand language.

Only male humpback whales (Megaptera novaeangliae) sing, and the behaviour is thought to be important for attracting mates. The songs are constantly evolving, with new elements appearing and spreading through the population until the old song is completely replaced with a new one.

鈥淲e think it鈥檚 a little bit like a standardised test, where everybody鈥檚 got to do the same task but you can make changes and embellishments to show that you鈥檙e better at the task than everybody else,鈥� says at Griffith University in Gold Coast, Australia.

Instead of trying to find meaning in the songs, Allen and her colleagues were looking for innate structural patterns that may be similar to those seen in human language. They analysed eight years of whale songs recorded around New Caledonia in the Pacific Ocean.

The researchers started by by creating alphanumeric codes to represent every song from every recording, including around 150 unique sounds in total. 鈥淏asically it鈥檚 a different grouping of sounds, so one year they might do grunt grunt squeak, and so we鈥檒l have AAB, and then another year they might have moan squeak grunt, and so that would be CBA,鈥� says Allen.

Once all the songs had been encoded, a team of linguists had to figure out how best to analyse so much data. The breakthrough came when the researchers decided to use an analysis technique that applies to how infants discover words, called transitional probability.

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鈥淪peech is continuous and there are no pauses between words, so infants have to discover word boundaries,鈥� says at the Hebrew University of Jerusalem. 鈥淭o do this, they use low-level statistical information: specifically, sounds are more likely to occur together if they are part of the same word. Infants use these dips in the probability that one sound follows another to discover word boundaries.鈥�

For example, in the phrase 鈥減retty flowers鈥�, a child intuitively recognises that the syllables 鈥減re鈥� and 鈥渢ty鈥� are more likely to go together than 鈥渢ty鈥� and 鈥渇low鈥�. 鈥淚f whale song has a similar statistical structure, these cues should be useful for segmenting it as well,鈥� says Arnon.

Using the alphanumeric versions of the whale songs, the team calculated the transitional probabilities between consecutive sound elements, making a cut when the next sound element was surprising given the previous one.

鈥淭hose cuts divide the song into segmented sub-sequences,鈥� says Arnon. 鈥淲e then looked at their distribution and found, amazingly, that they follow the same distribution found across all human languages.鈥�

In this pattern, called a Zipfian distribution, the prevalence of less common words drops off in a predictable way. The other striking discovery is that the most common whale sounds tend to be short, just as the most common human words are 鈥� a rule known Zipf鈥檚 law of abbreviation.

at the University of Sydney, who wasn鈥檛 involved in the study, says it is a novel way of analysing whale song. 鈥淲hat it means is that if you analyse War and Peace, the most frequent word will be twice as frequent as the next and so on 鈥� and the researchers have identified a similar pattern in whale songs,鈥� he says.

Team member at the University of Edinburgh, UK, says he didn鈥檛 think the method would work. 鈥淚鈥檒l never forget the moment that graph appeared, looking just like the one we know so well from human language,鈥� he says. 鈥淭his made us realise that we鈥檇 uncovered a deep commonality between these two species, separated by tens of millions of years of evolution.鈥�

However, the researchers emphasise that this statistical pattern doesn鈥檛 lead to the conclusion that whale song is a language that conveys meaning as we would understand it. They suggest that a possible reason for the commonality is that both whale song and human language are learned culturally.

鈥淭he physical distribution of words or sounds in language is a really fascinating feature, but there鈥檚 a million other things about language that are just entirely different from whale song,鈥� says Enfield.

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published this week, at Stony Brook University in New York found that other marine mammals may also have structural similarities to human language in their communication.

Menzerath鈥檚 law, which predicts that sentences with more words should be composed of shorter words, was present in 11 out of 16 cetacean species studied. Zipf鈥檚 law of abbreviation was found in two out of five species where available data made it possible to detect.

鈥淭aken together, our studies suggest that humpback whale song has evolved to be more efficient and easier to learn, and that these features can be found at the level of notes within phrases, and phrases within songs,鈥� says Youngblood.

鈥淚mportantly, the evolution of these songs is both biological and cultural. Some features, like Menzerath鈥檚 law, may emerge through the biological evolution of the vocal apparatus, whereas other features, like Zipf鈥檚 rank-frequency law [the Zipfian distribution], may require the cultural transmission of songs between individuals,鈥� he says.

To understand the impacts on dolphins, his team monitored the response of pods off the coast of California as sonar devices were dipped into the sea at specific locations by military helicopter. They found that “these animals can detect and respond to these types of signals in different ways in terms of changing or calling behaviour, in terms of changing movement and speed and spacing”, says Southall. It is hoped that insights into how sonar affects their social dynamics can be used to mitigate harm in the future.

Dolphins in the Gulf of Mexico are inhaling microplastics, which could lead to lung problems.

Researchers at the College of Charleston in South Carolina carried out routine catch-and-release health assessments on five bottlenose dolphins (Tursiops truncatus) from Sarasota Bay, Florida, and six from Barataria Bay, Louisiana, in May and June 2023.

As part of the checks, they held a petri dish above the animals鈥� blowholes, looking for any tiny bits of plastic in their breath.

To make sure these dishes weren鈥檛 simply picking up microplastics floating in the air anyway, the researchers held a second petri dish away from the blowholes to collect control samples.

They found that all of the dolphins exhaled microplastics. Fifty-four such pieces were collected in total, each smaller than 500 microns.

This shows that dolphins are breathing in microplastics, says team member . 鈥淭hese particles are everywhere, regardless of urbanisation and human development.鈥�

Dziobak expects similar results would occur in other parts of the world. 鈥淢icroplastics are super small and super lightweight, which makes them easy to transport,鈥� she says. 鈥淪ome researchers have shown microplastics can travel through the air for thousands of miles.鈥�

The team didn鈥檛 investigate whether these particles were harming the dolphins, but previous research suggests they could be.

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鈥淲hat we know from human studies is that inhaling microplastics can lead to lung inflammation and other respiratory problems鈥� says Dziobak. 鈥淪ince we observed similar particles in the exhaled breath of dolphins as have been reported in humans, dolphins might also be at risk for lung problems.鈥�

at the University of Adelaide in Australia says she would be interested to know exactly how these microplastics could be impacting dolphins. 鈥淎 lot of research indicates that although health impacts are known to occur, the microplastics have to contaminate the animal in quite high concentrations,鈥� she says.

鈥淔inding microplastics in marine species is now unfortunately a norm, and most specimens that are investigated commonly have them. Dolphins are often an indicator of marine ecosystem health, so this finding supports the fact that microplastics really are ubiquitous.鈥�

The first-ever footage of a blue whale calf suckling, filmed by a snorkeller in East Timor in South-East Asia, has been released.

鈥淚t is certainly not a newborn calf,鈥� says 聽at the Australian National University in Darwin, 鈥渂ut it鈥檚 clearly still suckling.鈥�

Edyvane says capturing the footage was an extraordinary achievement that had never been managed before anywhere. The behaviour was filmed by a snorkeller on an eco-tourism voyage in 2022 who was swimming with pygmy blue whales off the coast of the nation鈥檚 capital, Dili, but has only been released now.

(Balaenoptera musculus) are the largest known animal to have ever lived on Earth and can reach lengths of over 30 metres and a weight of almost 200 tonnes. The subspecies of pygmy blue whales (Balaenoptera musculus brevicauda) found off East Timor are marginally smaller, reaching maximum lengths of 24 metres.

Blue whales calves don鈥檛 attach to their mother when they feed 鈥� she releases oily milk into the water, which is then swallowed by the calf.

The feeding calf in the video is large, says Edyvane, and probably in its second year with its mother 鈥� blue whales wean at three years.

Other key blue whale behaviour has been glimpsed and filmed in the area as part of a decade-long research and . Edyvane, who leads the project, says that a database of 2700 pygmy blue whales has been collected since 2014, revealing that East Timor may host one of the world鈥檚 biggest migrations of the creatures.

Newborn calves, courtship and pre-mating and feeding behaviour have all been confirmed.

鈥淲e haven鈥檛 seen a penis yet, but we have seen some very amorous adults getting very funky with each other,鈥� says Edyvane.

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at Western Australia鈥檚 Department of Water and Environmental Regulation, says until recently no one realised just how many blue whales were migrating off East Timor.

Capturing the footage was incredibly fortuitous, she says. Blue whales are often far offshore in areas that are hard to get to, says Beck. 鈥淭o even be able to be in the water with blue whales is incredibly rare, let alone to be in the water at the right time and the right place to film a calf suckling.鈥�

The Amazon basin was once home to freshwater dolphins that grew up to 3.5 metres long 鈥� making them the largest river dolphins known to science.

Researchers made the surprise discovery during a 2018 expedition in Peru, says at the University of Zurich in Switzerland. The team saw the animal鈥檚 fossilised skull poking out of a river embankment and knew right away it was a dolphin. Close analysis confirmed the giant skull was unlike any ever found.

The researchers have now named the new species Pebanista yacuruna. The name honours a mythical aquatic people 鈥� the Yacuruna 鈥� believed to inhabit underwater cities in the Amazon basin.

The 16-million-year-old fossil was unearthed in a region that was once covered by a lake that was 鈥渋nsanely big 鈥� almost like a little ocean in the middle of the jungle鈥�, says Benites-Palomino. Based on the small size of the ancient dolphin鈥檚 eye sockets and its large teeth, he says P. yacuruna was probably a predator with poor eyesight. It relied heavily on echolocation to find fish. 鈥淲e know that it was living in really muddy waters because its eyes started to reduce in size,鈥� says Benites-Palomino.

Because the fossil was found in the Amazon basin, the researchers expected its closest living relatives to be modern Amazon river dolphins. Instead, they found P. yacuruna was more closely related to river dolphins of South Asia. Like them, this ancient species has raised crests on its skull that improved its ability to echolocate.

P. yacuruna may have been driven extinct during a broader ecological shift, says Benites-Palomino. 鈥淎round 11 to 12 million years ago, this mega wetland system started to drain, giving way to the modern Amazon. A lot of species disappeared at that moment, and that might also have been the fate of this giant dolphin.鈥�

Bottlenose dolphins have an extra sense 鈥� the ability to feel electric fields 鈥� which they may use to navigate and search for food.

The power to sense weak electric fields, known as electroreception, is common among water-dwelling animals, such as sharks, platypuses and rays.

鈥淚t鈥檚 a pretty old sensory modality,鈥� says at the University of Rostock in Germany. 鈥淚t鈥檚 really developed several times across different species.鈥�

Some of these animals generate their own electric signals to sense their surroundings, communicate with others or stun prey.

In 2011, the Guiana dolphin (Sotalia guianensis) became the first marine mammal known to have an electric sense.

Now, H眉ttner and his colleagues have found that a second species of dolphin, bottlenose dolphins (Tursiops truncatus), can also detect electric fields.

Bottlenose dolphins are born with whiskers along their snouts which fall out as they grow up, leaving deep follicles where they used to be.

鈥淚t鈥檚 like an empty bag in the skin,鈥� says , also at the University of Rostock. Inside these pits are cells that strongly resemble electric field-detecting receptors that have been found in sharks, he says.

To confirm if they have the power of electroreception, the team decided to put two female bottlenose dolphins at Nuremberg Zoo in Germany, Donna and Dolly, to the test.

In a 12-metre-wide circular pool, each dolphin was trained to rest its head on a metal platform and swim away if it sensed an electric field, which was generated by copper electrodes in the water. If they responded correctly to the stimulus, the dolphins would be rewarded with fish.

Both dolphins excelled at the activity for electric fields as weak as 5.5 microvolts per centimetre.

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The team also found that the dolphins reacted to alternating fields, which simulated the pulsating electrical signals that would be given off by fish in nature.

The findings suggest that bottlenose dolphins may well use this sense to hunt for nearby fish, and perhaps even navigate the oceans using Earth鈥檚 electric field. But studies of dolphins in the wild are needed to confirm this, says Dehnhardt.

鈥淎n exciting direction will be to compare the molecular basis of electroreception across dolphins, bees, platypus, with the slightly more defined properties in fishes to understand evolutionary mechanisms of this incredible sensory ability,鈥� says at Harvard University.