Even though it is 4 metres long, this humpback whale calf was no match for a group of dusky sharks

Species: Dusky shark (Carcharhinus obscurus, pictured below)

Habitat: Temperate and subtropical waters worldwide

You’re never big enough to be safe. At least one type of shark seems to have a taste for baby whales.

Spotted off the eastern coast of South Africa, in the Pondoland Marine Protected Area, a humpback whale calf some 4 metres long endured a harrowing ordeal, beset by a group of dusky sharks, each 2 to 3 metres long.

These beasts tend to dine on fish found in coastal and pelagic waters and occasionally marine mammals such as dolphins and porpoises.

But on this occasion, they were more adventurous.

Witness to an attack

For a couple of hours the humpback whale calf swam in circles, pursued by between 10 and 20 sharks, says cinematographer Morne Hardenberg, who witnessed the encounter (see top picture).

The calf was bitten many times, thrashed vigorously at the surface when attacked, and attempted to swim away.

“We stayed with it for a while and it was doing the same manoeuvring, with the sharks following it, and then it just disappeared,” he says. The calf probably drowned from exhaustion, its carcass never recovered – it’s not clear if the sharks ate it in the end.

This is the first time any shark has been directly documented attacking a whale. Other species, such as tiger sharks, are known to be partial to whale meat, but they get it by scavenging.

Matt Dicken from the KwaZulu-Natal Sharks Board in South Africa, who with his colleagues published a report of the incident, believes that such attacks might be more common than we think. “It’s still probably quite rare, but they are happening,” he says.

The East African humpback whale population is growing, so we might see more shark attacks in future, Dicken’s paper suggests.

Apart from humans and the occasional orca known to attack babies, whales don’t really have predators, probably simply because of their size. Humpbacks, for example, grow to some 15 metres long.

Ancient whale eaters

But it wasn’t always like this. The massive megalodon shark, which , is thought to have preyed regularly on baleen whales, says Samuel Gruber of the Bimini shark lab in the Bahamas. The evidence for this comes from megalodon tooth marks found on whale bones.

Still, sharks are unlikely to pose a regular danger to healthy whale calves, Gruber says, suggesting this calf might have been injured. Or it may have been abandoned by its mother, says Dicken, and so was more vulnerable.

Sardine run

So was this an organised attack to secure dinner?

Sharks are highly social and can hunt cooperatively, says Gruber. This observation happened during the sardine run, a vast fish migration in which cooperative feeding is observed with several shark species, dolphins, sea lions and sea birds, he says.

Dicken doesn’t think that the sharks were actually hunting together. They were probably just aggregating around the calf attacking it opportunistically, he says.

Journal reference:

Read more: “When humans attack: The fallout of the shark slaughter“; “Deep sea special: The curious afterlife of whales”

(Images: Top – Morne Hardenberg; Second – Flip Nicklin/FLPA)

The poster child for evolution may have finally revealed its secret. More than 1000 closely related but different species of cichlid fish live in Lake Malawi in south-east Africa – more than in any other lake in the world.

“They are remarkable,” says at the University of Syracuse in New York. The huge number of closely related species living together has meant they feature prominently in models of species diversification. But what made them so diverse has remained a mystery.

Some think environmental forces drove the diversification, others that the underlying cause was biological, says Scholz. For example, some females are colour-blind to males that are a different colour to them, which can drive sexual isolation between different groups of fish.

To try and settle the debate, Scholz and his team examined sediment records from the lake covering 1.3 million years. They found that over this period the water levels dropped by more than 200 metres around 24 times.

Forced diversification

These dramatic changes would have changed the habitat, says Scholz, as less water in the lake would shift the rocky shoreline inwards, alter the pH and salt levels of the water, and even separate the lake into smaller ones. This would ultimately force the fish to adapt to the new conditions and diversify.

What is remarkable is that even after the lake reformed and the fish came back together again, they managed to stay distinct, says George Turner at Bangor University in the UK.

Understanding how they achieved this will require studying the genetic basis for their subtle differences in behaviour, mating signals and feeding apparatus, he says.

Thomas Kocher at the University of Maryland isn’t convinced that the changes in the lake water levels alone drove the diversification of cichlids.

What the findings do show, however, is why the cichlids came to dominate the lake: they were able to “out-evolve” other groups of fish while these changes were occurring, he says.

But cichlids aren’t the only group of animals with an enormous number of species, says Scholz. For example, there is a wide variety of snails in Lake Tanganyika, just north of Lake Malawi. He now wants to see whether similar changes may explain biodiversity in other lakes as well.

Journal reference: PNAS, DOI: 10.1073/pnas.1512864112

Read more: “Dark secret of the lake”

Image credit: Cristian Umili / VWPics/age fotostock/ Superstock

It sounds like the stuff of nightmares: a sudden drop in cabin pressure on board your flight. This can lead to hypoxia – a lack of oxygen – causing passengers and pilots to pass out. Now nervous flyers can breathe a little easier, thanks to a new device that warns pilots of the condition.

Although rare, sudden pressure drops do occasionally affect both military and commercial flights. One such event was thought to have caused a plane crash near Marathon in Greece in 2005, killing all 121 people on board.

Planes are equipped with oxygen-monitoring sensors, but that may not help if the crew are already affected by hypoxia, says , who specialises in aerospace medicine, or if they misinterpret the signals, as is thought to have occurred in the 2005 crash, says Daniel Rooney at the Institute of Aerospace Medicine in Cologne, Germany.

By the time these sensors alert a pilot to a drop in oxygen, it can already have had a major effect on their decision-making and awareness. And if the air pressure drops suddenly - as can happen during military manoeuvres – even pilots specially trained to spot hypoxia can have little time to do so before losing consciousness.

Non-invasive check

Now a team from Wright-Patterson Air Force Base in Dayton, Ohio, has developed a real-time sensor to warn pilots of hypoxia. The work is part of a larger effort to monitor the physiology of military pilots, including aspects like stress or fatigue, in a non-invasive way, says team leader Claude Grigsby.

The sensor works by measuring levels of chemicals called volatile organic compounds present in exhaled breath. By testing the sensor on volunteers during a simulation in which oxygen levels were cut, the team was able to identify a set of VOCs signalling the onset of hypoxia. Continuous monitoring of breath for this set could alert a pilot to hypoxia in real time.

The team now aims to incorporate this technology into the standard military aircrew mask to continuously assess pilot safety, says Grigsby.

Pilot Patrick Smith, who runs the website , says the technology is likely to be more useful for private aviation than commercial airlines.

However, Grigsby says the idea of identifying biomarkers in breath could be applied to monitoring various aspects of health, such as fatigue, in commercial pilots too.

Journal reference:

(Image credit: Anstock/Alamy Stock Photo)

NO, THAT’S not a minor character from the latest Star Wars movie. This exotic-looking creature with its anteater-like snout is Tropidophora cuvieriana, an example of the incredible diversity and, yes, strange beauty of land snails.

“Most people think land snails are just ugly and slimy, and some are,” says photographer Ingo Arndt. “But many species are also very beautiful and show interesting behaviour.”

He decided to photograph the land snails’ beauty and coloration as he travelled around the world. He saw a wide variety of shell colours and patterns, for example (below, from top to bottom) the tree snail of the genus Amphidromus; the Cuban land snails Polymita venusta and Polymita picta iolimbata. Caracolus excellens has a distinctive flat, black shell. “I think these animals deserve it that we show their beautiful side,” he says.

But Arndt also wanted to bring the snails’ plight to the public’s attention. Like other animals, habitat destruction and pollution mean that thousands of snail species are endangered. Around a tenth of the 200 known species have probably disappeared.

These beauties also face another threat: shell collectors. With the Cuban snails in particular, Arndt notes that many are smuggled out of the country to fill collections across the globe. “Some important areas are already empty [due to collectors],” he says.

This article appeared in print under the headline “Here’s lookin’ at you”

Not a fan of slow jams? Maybe you haven’t had enough training.

When we hear speech, electrical waves in our brain synchronise to the rhythm of the syllables, helping us to understand what’s being said. This happens when we listen to music too, and now we know some brains are better at syncing to the beat than others.

Keith Doelling at New York University and his team recorded the brain waves of musicians and non-musicians while listening to music, and found that both groups synchronised two types of low-frequency brain waves, known as delta and theta, to the rhythm of the music.

Synchronising our brain waves to music helps us decode it, says Doelling. The electrical waves collect the information from continuous music and break it into smaller chunks that we can process.

But for particularly slow music, the non-musicians were less able to synchronise, with some volunteers saying they couldn’t keep track of these slower rhythms.

Practice makes perfect

Rather than natural talent, Doelling thinks musicians are more comfortable with slower tempos because of their musical training. As part of his own musical education, he remembers being taught to break down tempo into smaller subdivisions. He suggests that grouping shorter beats together in this way is what helps musicians to process slow music better.

One theory is that musicians have heard and played much more music, allowing them to acquire “meta-knowledge”, such as a better understanding of how composers structure pieces. This could help them detect a broader range of tempos, says of the University of Cambridge.

A similar process helps with decoding speech, but it can malfunction in conditions like dyslexia. Because the brain circuits for speech and music overlap, Doelling’s finding suggests that music training may be a way to help dyslexic children, says of Northwestern University in Evanston, Illinois.

Goswami agrees: her team has already shown that rhythm-based musical training seems to help .

Journal reference: PNAS, DOI: 10.1073/pnas.1508431112

(Image: H. Armstrong Roberts/ClassicStock/Getty)

The lion may be losing its position as king of the savannah.

Almost all large populations of the animal in West and Central Africa are declining, and may halve within 20 years. The situation is similar in East Africa.

But there is a glimmer of hope: lion populations in Southern Africa are stable or increasing. This is encouraging because it means that it might be possible to reverse the downward trends seen in East and West Africa, says of the University of Oxford’s Wildlife Conservation Research Unit.

Bauer and his colleagues analysed existing data on populations in different parts of Africa, identifying declines across much of the continent and then modelling future trends.

There are left in the wild – down from more than 200,000 a century ago. But it is hard to get reliable numbers of lion populations, says Stephanie Dolrenry of the conservation charity .

The three main explanations for this decline are a loss of habitat caused by a rise in the human population, the depletion of prey through hunting, and conflict with humans who perceive lions as a threat to their livestock, says Bauer.

These results yield yet another scientific indication of how imperiled lions are, says from the conservation organisation The African People & Wildlife Fund. Yet, she adds, there is little international awareness or recognition that an African icon of the wild is at risk.

Fenced communities

But in Botswana, Namibia, South Africa and Zimbabwe, where most lions live in fenced reserves that are heavily managed, lion populations have been growing. This is both good and bad, says Bauer.

Lions in these reserves are provided with extensive vet care and even extra prey. But what this means, says Bauer, is that in 20 years we will be mostly left with lions living in artificial conditions rather than roaming in true wilderness. An additional concern is that fencing may also affect other species beyond lions, says Lichtenfeld.

Bauer believes that artificial management should be combined with more traditional conservation efforts to ensure lion survival in a more natural environment.

Dolrenry agrees. Conservation efforts should include maintaining the lion habitats and working with local communities outside of fenced areas to teach them to tolerate living with wildlife and so minimize the number of lions killed, she says.

“We know very well what we need to do to save the lions,” Bauer says, but the problem is lack of resources and political will. “What we need now is implementation,” he adds.

This, he says, would not only save the lions, but also the biodiversity around them.

This is because lions play a key part in the ecosystem, as a so-called keystone species. The loss of lions has a knock-on effect on other organisms in their environment, such as the zebras they prey on and plants that prey eat, says Bauer.

Journal reference: PNAS, DOI:

Read more: “Rewilding: Bring in the big beasts to fix ecosystems”

Read more: “Last of the lions”

Image credit: Chris Johns/National Geographic Creative

Flowers are not enough, it seems. For the first time, bees have been discovered farming fungus to provide extra food for their larvae.

Though farming is well known in many social insects, such as ants and termites, bees have always been thought to depend solely on pollen and nectar for sustenance.

But for the Brazilian stingless bee, Scaptotrigona depilis, fungus may mean the difference between life and death.

What’s more, if other bees also depend on fungus for survival, the discovery has serious implications for the use of fungicides in agriculture.

of the Brazilian Agricultural Research Corporation, was studying the bees in the lab and originally mistook the white Monascus fungus growing in their hive for contamination.

Integral to the hive

But when he found it in all 30 hives he looked at, he began to suspect it was there for a reason, especially since it was growing inside brood cells – the structures that social bees build to house their growing larvae.

He and his team discovered that the fungus is a key part of the hive. It permeates the cerumen, a material made of wax and resin that the bees use as building material. After the bees have deposited regurgitated food for the larvae inside the cells, and laid an egg, the fungus starts growing.

Once the egg hatches, the larva feeds on the fungus, and it turns out this food is absolutely crucial. When the team tried to grow the bees in the lab without the fungus, the survival rate of the larvae dropped dramatically – from 72 per cent to just 8 per cent.

The survival difference may be either due to some nutrients provided by the fungus, or due to the fungus protecting the regurgitated food from spoiling, they say.

Portable farm

When bees leave to start a new colony, they take some of the cerumen with them to build the new hive structures, so their fungal farm comes too.

“It is clear that the fungus profits from dispersal with the bees, both to new colonies and within the nest, and is offered a protected environment,” says of Wageningen University in the Netherlands.

Menezes calls it “proto-farming”, as the bees don’t seem to actively tend to the fungus. But they do “plant” it, provide stable growing conditions and food, harvest the crop and depend on it – all features of farming seen in other social insects, such as ants and termites. One ant species even farms animals for meat. And some fungi are farmers themselves, of bacteria.

Fungicide concern

“It is an exciting example of the complex connections between insects and microscopic life,” says of the University of Wisconsin. “And it illustrates the important roles for beneficial symbionts in insects.”

Both Menezes and Currie think there are more farming bees to be found. “Given the substantial diversity of bees, many of which are poorly studied, it is likely that other bees engage in similar associations,” Currie says.

This raises concern about the use of fungicides, which while not directly harmful to bees, may be affecting them by killing off their symbiotic fungi, Menezes’s team concludes.

Journal reference: Current Biology, DOI: 10.1016/j.cub.2015.09.028

Read more:“This means spore: The brutal world of fighting fungi”

(Image: Cristiano Menezes)

In the depths of the ocean, the boundaries between two different domains of life, bacteria and archaea, seem to blur.

Dwelling together in seabed sediments, these microorganisms link up to form extensive power grids, ones that ultimately allows them to oxidise methane in the ocean.

The process ensures that vast stores of this greenhouse gas are not released into the atmosphere. But how this microbial partnership manages to do this in the oxygen-free conditions here has been a puzzle for decades.

“The crazy thing is that our Earth is the way it is because of these consortia,” says at the Max Planck Institute for Marine Microbiology in Bremen, Germany. “Our climate depends on them.”

Two studies, one led by Boetius, the other by in Pasadena, seem to have solved the puzzle. The bacteria form minuscule nanowires to connect with archaea – and this allows a mutually beneficial process to take place.

For aerobic organisms such as ourselves, food is “burned” in the presence of oxygen to generate energy. But this is not an option for the microbes living at depth, where there is no oxygen. These bacteria essentially do the same thing with sulphate instead of oxygen.

What happens is that the archaea break down methane for energy, but they need a place to dump the electrons that this liberates. They transfer the electrons to the bacteria, which add them to sulphate. This allows the bacteria to produce ATP, the energy “currency” of cells.

By cooperating, both benefit from a reaction that neither could carry out on their own.

Nanowires exposed

For Boetius, the breakthrough came when they found out how to view the nanowires using an electron microscope. “They were so few and so fine, they could only be seen under specific conditions,” she says.

Although Orphan’s team did not detect the nanowires, they were able to exclude the possibility that the electrons were simply being exchanged via the environment.

Using nanowires to transfer electricity could allow the microbes to grow faster than if they exchanged them indirectly, says Boetius.

The finding is exciting because it explains how organisms that appear separate can exchange electricity, says microbiologist Lars Peter Nielsen from the University of Aarhus in Denmark.

The images of the nanowires are compelling, says says geobiologist at the Rensselaer Polytechnic Institute in New York, although he remains cautious until direct measurements are made, preferring instead to call them “wire-like things”.

But they do also add to the growing list of organisms that feed off or transfer electricity, says Gorby, all of which seem to achieve this in different ways. “We have only just begun to scratch the surface of understanding life of the world’s first electricians,” he says.

“We better get used to it – electrons are probably key elements in many microbial interactions,” agrees Nielsen.

Superorganisms

The microorganisms are so tightly bound together by the nanowires that they have not even been able to take them apart, Boetius says.

Her team is planning to look at whether the archaea and bacteria have actually exchanged genes at some point, including those involved in electron transfer. This will provide clues as to whether they co-evolved, but also highlights the question of how separate they really are with respect to their metabolism and their ability to thrive without each other.

“These microbial consortia in many ways appear as superorganisms, but the partners are also separate species, that all have to gain from the overall process to make it sustainable,” says Nielsen.

Gorby thinks of such communities as microbial tissue rather than a superorganism. “Electrical connections among trillions of individual cells, each orchestrating their own complete metabolic network – for me that was a game changer,” he says.

Journal reference: Study by Boetius et al.: ; study by Orphan et al.:

Read more: “Live wires: The electric superorganism under your feet”

(Image credit: Gary John Norman/Getty)

The war on drugs has taken an interesting turn. In , businessman Richard Branson said that the was planning to release a statement at the recommending that governments decriminalise all illegal drugs. A long-time advocate of changing drug policies, Branson wrote that he “could not be more delighted” with this apparent development.

The UNODC has since saying that the briefing paper mentioned by Branson isn’t a final or formal document and that there has been an “unfortunate misunderstanding” regarding the intention of the document.

It does, however, state that a document is under review. So, if such a recommendation were to be released in the future, governments across the globe would need to decide whether to follow Portugal’s example. The country “de-penalised” the use of all drugs in 2001.

, chair of the UK’s Independent Scientific Committee on Drugs and former UK government advisor, says that he would fully support such a move from the UNODC. “For recreational drug users criminalisation will do more harm than the drugs they use, and for addicts they need to be treated for the illness they suffer, not persecuted,” he says.

Alex Stevens, professor of criminal justice at the University of Kent, UK, also supports such a potential move. He notes the many drawbacks of criminalisation, including discouraging “people who need treatment for drug dependence from seeking it”.

Relaxed laws

Governments are already considering the question. The Oireachtas Joint Committee on Justice, Defence and Equality in Ireland, which met last week to discuss changes in drug policy following a recent visit to the Portuguese capital Lisbon, is expected to recommend to the Irish government the decriminalisation of the possession of small amounts of drugs, .

Many other countries have already introduced more relaxed laws, says Caitlin Hughes at the National Drug and Alcohol research Centre in Australia. These include Armenia, Belgium, Chile, the Czech Republic, Estonia and Mexico.

One of the main arguments against decriminalisation is that it will normalise drug use, encouraging more people to consider taking them. Looking at Portugal – where those caught in possession of drugs are given an administrative punishment, like community service or a fine, or medical treatment if they are addicted – offers an opportunity to test this claim.

An analysis of the effects of Portugal’s drug policy found that, although there were small reported increases in the use of soft drugs such as cannabis among adults, the use of what is known as “problematic drugs”, in particular injectable ones like heroin, . An analysis from the 1970s in the US came to a similar conclusion, finding that related to other drugs.

Portugal also has one of the according to the European Monitoring Centre for Drugs and Drug Addiction, as well as one of the lowest rates of drug-induced deaths among adults in Europe – 3 deaths per million in 2012 compared with the European average of 17.2 deaths per million.

Reduced harms

“Decriminalisation does not generally lead to increases in drug use or related harms,” says Stevens. “Despite politicians’ claims, the evidence suggests that young people do not take their cues from the legal status of drugs when deciding whether to use them.”

Nutt agrees: “The Portuguese and other models show us the decriminalisation approach reduces costs and harms and saves lives.”

Decriminalisation may also allow the police to focus on more serious crimes, says Stevens. He points to when people found with small amounts of cannabis were let off with a warning. Stevens says this approach freed up police to commit resources to other forms of crime – that subsequently fell.

But could it ever happen, politically? The key thing is that such a policy statement by the UNODC would lend the authority of the agency to the decriminalisation of drug use, says Hughes.

“The biggest challenge in reform remains politics and public perception and this is where the public support for decriminalisation of illicit drug use and possession from the UNODC could lead to significant additional reform and improvement in public health,” she says.

Image credit: Spencer Platt/Getty

Just make lots of noise and we’ll be fine (Image: Joel Jorgensen/Nebraska Game and Parks Commission)

Dense fog can not only ground planes but also birds – just not always.

of US Geological Survey’s Upper Midwest Environmental Sciences Center in La Crosse and her colleagues were observing sandhill cranes in the Horicon wildlife refuge in south-east Wisconsin one November morning. Heavy fog settled, but the cranes still set off from their night roost to reach foraging areas, albeit later than usual.

This provided a rare opportunity to study how birds behave when flying in heavy fog. The cranes flew cautiously, staying close to the roost, and went in circles rather than straight lines.

“They were going every which direction, which we’ve never seen before,” says Kirsch. She thinks they were probably reluctant to fly further than they could see and also wanted to keep the flock together.

They also vocalised much more frequently and loudly than normal. This is common among birds flying in low-visibility conditions, says at the University of Birmingham in the UK. It probably allows them to stay in touch when they cannot be seen.

When there is fog, mist or heavy rain, larger birds such as cranes, ducks and geese usually prefer to stay put until conditions improve. “They can afford not to venture to foraging grounds for a couple of days,” says Martin.

Kirsch thinks hunger and their impending southern migration might have driven the sandhill cranes to flight, despite the poor visibility. “It was very cold, and energetically they needed to eat,” she says.

Night-time challenge

But if some birds avoid flying in fog, how come many other species are happy to fly at night? Kirsch says that most birds that do so typically set off at sunset, when there is enough light available for them to orient themselves.

And like airplane pilots, night-time flyers don’t rely only on vision. They also navigate using acoustic and magnetic cues, as well as the positions of the stars and moon, says of Cornell University in Ithaca, New York.

But even so, they can get confused. Light pollution is a particular concern for nocturnal flyers like songbirds, which are drawn to artificial light. And if they are dazzled, they also display circling flight behaviour, says Farnsworth.

Fog and darkness aside, many birds are betrayed by their own eyes even in broad daylight, says Martin. Some literally can’t see straight ahead while flying and trying to track prey or predators at the same time. The placement of their eyes means that they have several blind spots that make them prone to crashing, in particular into artificial structures like transmission lines and towers, which they don’t expect to encounter.

Birds that dive for food face the additional challenge of seeing underwater. This can be difficult even for birds with keen sight.

Puffins and guillemots, for example, are not particularly vulnerable to crashing when airborne, but are prone to being entangled on gill nets. Martin and his colleagues have found that this is because the peculiarities of their visual fields mean that they may not be able to see straight ahead in the water.

Journal reference: