The end of war doesn鈥檛 necessarily bring peace to the environment. An increase in illegal logging could be one of the unexpected consequences of peace in Colombia.

In 2016, the Colombian government signed a peace agreement with the guerrilla group FARC (The Revolutionary Armed Forces of Colombia), ending the longest war in the Americas. During the 52-year-long conflict, as many as 220,000 people are reported to have died and millions were displaced.

But the armed group may unexpectedly have helped protect the regions it occupied from deforestation. As the group disbands, conservationists fear the lush forests it occupied will be left vulnerable to illegal logging.

鈥淣ow, that FARC is gone, there is nobody controlling the deforestation 鈥� because actually when they were here, they had some rules about it,鈥� says at the University of Queensland in Brisbane, Australia, who has been studying the relationship between armed conflicts and conservation in Colombia.

In areas under FARC control, the organisation often took on the role of a local government, .

Logging rise?

鈥淣ow there is no one to oversee the land,鈥� says Negret Torres. 鈥淭he government hasn鈥檛 come in yet, but everybody else has and they log.鈥�

Negret Torres has looked at the number and distribution of armed conflicts across Colombia between 2000 and 2014, comparing the data with levels of deforestation in the country鈥檚 various regions. He found that wherever FARC guerrillas were present, deforestation activity was lower than in conflict-free areas. He presented his results at the in Cartagena, Colombia, last week.

Negret Torres hasn鈥檛 quantified the difference yet. In total, almost 3 million hectares of forest have been lost in Colombia from 2001 to 2015, according to

The impact of war on natural environments is unpredictable. The in the Democratic Republic of the Congo became a site of conflict in the 1990s and 2000s: the local environment suffered as fighters killed wildlife and felled trees, . But war in Sierra Leone during the 1990s had the opposite effect. There 鈥� as in Colombia 鈥� .

The Colombian government has plans to increase its control of the country鈥檚 forests. By 2018 it intends to protect more than 鈥� up from nearly at present.

Budgets cut

鈥淲e are working with former members of FARC to implement environmental policies, and training them to help conserve areas,鈥� Luis Gilberto Murillo, the Colombian Minister of the Environment and Sustainable Development told the conference. 鈥淭his is also a way for FARC to reincorporate to the civil life.鈥�

However, the Colombian government recently announced that the , leaving conservationists doubtful that there will be enough money to fund the promised expansion of the protected areas.

at Oregon State University, who also intended the conference, worries about the effect of deforestation in formerly untouched forests. 鈥淓ven just initial logging on intact forests has a much worse impact [on biodiversity] than in areas already exposed to deforestation,鈥� he says.

Such deforestation is made more likely by the fact that millions of people displaced by the conflict could return home, and may need to find a new source of income.听 鈥淚f you have poverty, people will turn to the forest,鈥� says Betts. 鈥淎nd you could also have hunting for bush meat out of control.鈥�

, and many still haven鈥檛 been fully explored because of the decades-long turmoil. 鈥淭here are species and forests being preserved,鈥� says Negret Torres. 鈥淏ut a peace where we are able to prioritise places important for conservation would be the best.鈥�

听

Some bombs can help create life. A rich mix of rare saline water species have been found thriving in ponds formed in second world war bomb craters in Hungary.

As the number of natural inland ponds dramatically drops throughout Europe due to agricultural land drainage and urbanisation, this discovery backs the case for the inclusion of human-made habitats into conservation initiatives.

鈥淭hese 鈥榳artime scars鈥� might be unnatural, but still can be regarded as valuable bioreserves 鈥� just like sunken warships or submarines scattered in the ocean that turned into coral reefs giving refugee to many species,鈥� says of aquatic ecosystem research centre WasserCluster Lunz in Austria, who led the research.

A series of miscalculated aerial bombings aimed at a local airport helped to create more than a hundred ponds near the village of Apaj in central Hungary. Similar bomb ponds exist worldwide as a result of war and military training.

The bombs in Hungary happened to fall on a type of habitat known as sodic meadows, which give rise to saline habitats when covered in water.

Naturally occurring inland saline ponds, called soda pans, are unique to this region of Europe. They form part of wider wetlands that harbour a high number of rare and endemic species 鈥� but they have been disappearing.

Salt-loving species

The researchers sampled various parts of 54 of these bomb crater ponds to assess the number and type of species living in them. In all, they identified 274 species, including water beetles and turtles, with most of them being salt loving, and several rare and near-vulnerable species.

Some peculiarities turned up: a rare algae (Halamphora dominici) that, apart from central Europe, is only found in Chilean salt lakes, and an also endemic fairy shrimp (Eubranchipus grubii) that has only been recorded twice in the last 25 years in Hungary.

鈥淭hese are very understudied habitats. Even though there are many bomb craters in the old war zones of Europe like England or Belgium,鈥� says Vad.

When the team compared life in the bomb crater ponds with their natural counterparts 鈥� the soda pans and lakes only present in the Pannonian basin of central Europe 鈥� they discovered that the biodiversity is comparable.

Artificial microhabitats

鈥淭hese craters could serve as excellent scientific models for soda water habitat research, and could have significance for certain species as microhabitats,鈥� says Orsolya Mile of Kiskuns谩gi National Park.

But we shouldn鈥檛 overstate their conservation importance, she says: larger, more complex natural soda lakes in the same area have much greater biodiversity.

Vad agrees the craters might be more of a secondary habitat than something to replace the natural pans. Some bomb craters in other parts of Hungary, considered to be unsightly reminders of the war, have already been filled in as part of work to restore grassland.

But as 80 per cent of natural soda pans in Kiskuns谩gi National Park have already disappeared, the crater ponds could still worth protecting, especially as a network connecting natural habitats, says Vad.

Read more: Ponds or pounding are both possible origins for life; Elephants鈥� footprints leave behind tiny oases for aquatic life; Icy pools are oases for unique glacier ecosystems

It was like identifying a criminal from a bit of DNA left at a crime scene. No murder mystery was solved, but researchers have found rare blind cave salamanders in five caves they were not previously thought to live in, thanks to the DNA the animals shed in water.

This extends the known range of the vulnerable salamanders and raises hopes for their long-term monitoring and conservation.

The olms (Proteus anguinus), or baby dragons as locals call them, spend their entire life in the underground waters of the Dinaric Alps running from Slovenia through Croatia and several other Balkan countries.

DNA from bits of skin that they have shed or their feces gets dissolved into their watery habitat and can be washed out of the cave. This is good news for biologists studying cave life, because most of the 7000 or so caves in Croatia are inaccessible to humans.

鈥淏efore you would only see these elusive animals if they were washed out of their home after heavy raining, or if you would actually go cave-diving,鈥� says Judit V枚r枚s of the Hungarian Natural History Museum who led the study. 鈥淏ut now we can tell just from some cave water if they are there or not.鈥�

Olm my goodness!

Her team used a technique known as environmental DNA, or eDNA, to survey the salamanders. 鈥淭his technique has been known for some time among conservation biologist, but until now it was never used for cave vertebrates,鈥� says V枚r枚s.

The team collected water samples from 15 caves across Croatia during the summer of 2014. They filtered 2 liters of water from each site through special paper, and then extracted the eDNA from the paper. They confirmed the presence of the salamander in 10 caves it was already known to inhabit, and detected the species for the first time in five others.

Croatian conservationists have now adopted this technique to map the olms鈥� habitat more precisely, and to learn more about their population genetics.

Although both caves and olms are protected in Croatia, V枚r枚s hopes discoveries with eDNA will accelerate the protection of the ground above the caves, since olms are very sensitive to pollution and contaminants can seep into their habitat from above.

Salamander in your hands

鈥淭his is an excellent use of eDNA, but it鈥檚 just a complementary tool,鈥� says Matthew A. Barnes of Texas Tech University. 鈥淚t鈥檚 never going to replace the hard evidence of having a fish, or a blind salamander in your hands.鈥�

In dark, cold caves, eDNA can stick around for a long time and could even get carried far from its source, leading researchers to make false assumptions about where the olms are, he says.

And little is known about the degradation rate of the olm eDNA, or eDNA in caves at all because that has never been studied in detail.

V枚r枚s agrees the method is not perfect. She says it can detect the presence of the animals within a cave system, but not necessarily narrow it down to a particular cave.

But she says it is a good way to identify cave systems with the animals, so the team can then examine those areas in more depth with traditional methods 鈥� sending divers, for example.

Read more: Meet the weird amphibian that rules the underworld; DNA sequencing turns rivers into ecosystem surveillance systems

A Japanese tech company has trained an AI to give love advice to troubled hearts.

NTT Resonant, which operates the Goo web portal and search engine, created a to answer people鈥檚 relationship questions, like a virtual agony aunt. The researchers chose to focus on this genre of query as 鈥渘on-factoid鈥� questions are difficult for AI to address.

鈥淢辞蝉迟 chatbots today are only able to give you very short answers, and mainly just for factual questions,鈥� says Makoto Nakatsuji at NTT Resonant. 鈥淨uestions about love, especially in Japan, can often be a page long and complicated. They include a lot of context like family or school, which makes it hard to generate long and satisfying answers.鈥�

Nakatsuji and his team trained their algorithm using almost 190,000 questions and 770,000 answers from the company鈥檚 Oshiete goo forum. Based on this data, they came up with a generic structure for answers that includes a sentence showing sympathy, a suggested solution to the problem, an additional comment and a note of encouragement.

The Oshi-el AI then selects and combines appropriate sentences to use from a database based on the words used in the question. To combat the ambiguous nature of certain words 鈥� 鈥渞elationship鈥�, for example, could refer to a romantic situation or a business partnership 鈥� they use the category or title of each question to give the AI more context.

Money for love

For now, the answers still come across as a bit scripted, but they make sense. 鈥淚 can see this is a difficult time for you. I understand your feelings,鈥� says Oshi-el in response to a 30-year-old woman who finds herself stuck in a love triangle (the response has been translated from the original Japanese). 鈥淚 think the younger one has some feelings for you. He opened up himself to you and it sounds like the situation is not bad. If he doesn鈥檛 want to have a relationship with you, he would turn down your approach. I support your happiness. Keep it going!鈥�

It might work for love advice, but this approach is limited. It wouldn鈥檛 be able to write an essay, says at Carnegie Mellon University in Pittsburgh, Pennsylvania. To be able to write a more comprehensive answer, an AI would need to actually 鈥渦nderstand鈥� the question. 鈥淲e don鈥檛 even have a clear definition of 鈥榰nderstanding鈥� [in the context of AI], so an AI can only grasp the very shallow surface of things,鈥� says Wang. 鈥淏ut I think in this case people don鈥檛 care whether the advice is correct or not. You can say whatever as long as it sounds good.鈥�

Eventually, Nakatsuji wants to be able to generate the advice word by word. 鈥淏ut it鈥檚 hard to get money for love,鈥� he says. 鈥淚f we develop it for [questions about] travel, we will be able to monetise it through hotels or restaurants.鈥�

Ants may be smarter than we give them credit for. Tool use is seen as something brainy primates and birds do, but even the humble ant can choose the right tool for the job.

at the University of Szeged in Hungary and his team offered two species of funnel ants liquids containing water and honey along with a range of tools that might help them carry this food to their nests.

The ants experimented with the tools and chose those that were easiest to handle and could soak up plenty of liquid, such as bits of sponge or paper, despite them not being found in the insects鈥� natural environment.

This suggests that ants can take into account the properties of both the tool and the liquid they are transporting. It also indicates they can learn to use new tools 鈥� even without big brains.

Some ant species are known to use tools, such as mud or sand grains, to collect and transport liquid to their nests. But this is the first time they are shown to select the most suitable ones, says team member Patrizia d鈥橢ttorre from the University of Paris-North, France.

Tool up

To investigate this behaviour, the team offered Aphaenogaster subterranea and A. senilis ants various possible tools, both natural, such as twigs, pine needles and soil grains, and artificial.

The ants experimented with the tools and eventually showed preference for certain tools 鈥� even unfamiliar ones. The ants would drop the tool into the liquid, pick it up and then carry it to the workers back in the nest to drink from.

Subterranea workers preferred small soil grains to transfer diluted honey, and sponge for pure honey. Most of them even tore the sponge into smaller bits, presumably for better handling.

Senilis started off using all the tools equally, but then focused on pieces of paper and sponge, which could soak up most of the diluted honey they were offered. This indicates that they can learn as they go along.

Factors such as the weight of the tools could also have influenced the ants鈥� choice, but the researchers believe the tools鈥� absorbency and ease of handling mattered the most.

Stuck for space

Aphaenogaster ants possibly developed such tool use because, unlike many other ants, they can鈥檛 expand their stomach, says d鈥橢ttorre. 鈥淭hey had to find a way to exploit the valuable resource of liquid food.鈥�

This way, when ants come across a fallen fruit or a dead insect in the wild, their fluids can be transferred to the nest for the rest of the colony.

As ants live in a highly competitive environment, natural selection may favour using such tools to help feed the colony, says at Roanoke College, Virginia.

And these ants may have been happy to try novel materials because which particular tools are available in their natural habitat varies according to the season.

鈥淢any other accomplishments of these small-brained creatures rival those of humans or even surpass them, such as farming fungi species or using 鈥榙ead reckoning鈥�, a sophisticated navigation to find their way back to the nest,鈥� says Banschbach. 鈥淭he size of brain needed for specific cognitive tasks is not clear.鈥�

鈥淭ool use in insects is largely genetically controlled and evolved from selection of advantageous genetic mutations,鈥� says Gavin R. Hunt at the University of Auckland, New Zealand. This is unlike most tool use in birds or primates, which begins as novel behaviour and can sometimes be enhanced through genetic changes, he says.

Read more: Squirrel monkeys teach themselves to eat and drink from a cup

The habitat of one of the world鈥檚 rarest and most elusive big cats is shrinking fast, with the latest pressure coming from frankincense collectors.

Only around 200 critically endangered Arabian leopards remain in the wild, with the largest population in Oman. And while the latest camera trap photographs show a small but thriving population in the country, the cats are being squeezed out by encroaching humans, which brings them into conflict with camel farmers.

鈥淲e have seen leopards moving away from areas where they used to be,鈥� says Hadi Al Hikmani, a wildlife biologist at the Office for Conservation of the Environment in Oman. 鈥淚n Jabal Samhan nature reserve they鈥檙e moving around 6 kilometres southwards, but in areas like Nejd, north-west of the Dhofar mountains, they鈥檙e moving northwards, where they were not found in the last 10 years.鈥�

The displacement is most likely due to an influx of people looking for fresh sources of valuable frankincense, used in perfume and incense.

鈥淎 small community that harvests frankincense trees has recently established some semi-permanent camps in the Jabal Samhan area, especially near water resources,鈥� says Al Hikmani.

Disturbed leopards

People disturb the leopards, but also hunt and scare away its natural prey, the gazelle and the ibex.

This is compounded by loss of habitat from livestock overgrazing and desertification, which means leopards have limited space for manoeuvre.

Closer association with humans is set to create more conflicts, as the leopards are also known to hunt camels. Al Hikmani fears people might not be willing to turn a blind eye on lost camel livestock in the long run.

To find out more about the Arabian leopards in Oman, Al Hikmani and his colleagues installed more than 100 camera traps between 2011 and 2015 around the Dhofar mountains, and collected more than 200 scat samples for genetic analysis.

Though they have only recorded 35 individuals so far, they estimate there are around 44 to 58 wild Arabian leopards left in Oman. This would make it the world鈥檚 biggest population, as only 200 wild animals are thought to be left across the Arabian Peninsula.

The leopard is facing problems across the Peninsula. Both wild and captive populations in neighbouring Yemen are under pressure from armed conflict there. 鈥淵emeni colleagues have told us of a leopard killed in the wild and others captured for sale outside the country,鈥� says Andrew Spalton, adviser for environmental affairs at the Omani government. 鈥淯nderstandably the people of Yemen have other priorities at this time.鈥�

Twin cubs

The leopards鈥� small population might mean they are highly inbred, which can endanger conservation prospects.

There are about 84 animals held in captivity in the Arabian Peninsula, mostly at four major locations in the United Arab Emirates, Saudi Arabia, Oman and Yemen. Reintroduction in Oman isn鈥檛 an option at the moment as officials fear more wild cats wouldn鈥檛 be met with approval from local farmers.

鈥淲hile we have some support from livestock farmers for animals in the wild, I doubt there would be much appetite for releasing more animals,鈥� says Spalton.

Nevertheless, recent camera trap photos reveal the small population is doing well, with sightings of mating leopards and newborn cubs. 鈥淭he leopards are continuing to breed and we have photos of cubs 鈥� even twins,鈥� says Spalton.

Ultimately, the future of this elusive cat in Oman depends on whether their last remaining habitat in the Dhofar mountains can be preserved.

鈥淭hey are the most biodiverse area of Oman and Arabia but they are also hugely important as rangelands for livestock,鈥� says Spalton. 鈥淯nfortunately we have yet to find a balance between livestock and wildlife.鈥�

Read more: Elusive Arabian sand cat spotted after 10 years鈥� disappearance; The mission to find the world鈥檚 rarest cat in jungles of Java

A city in Denmark is about to become the first in the world to provide most of its citizens with fresh water using only the energy created from household wastewater and sewage.

The Marselisborg Wastewater Treatment Plant in Aarhus has undergone improvements that mean it can now generate more than 150 per cent of the electricity needed to run the plant, which means the surplus can be used to pump drinking water around the city.

As well as regularly powering the entire water system of 200,000 people living in the inner city area, any excess electricity could be sold into the local grid.

鈥淲e are about to be the first energy neutral catchment area,鈥� says Mads Warming of Danfoss Power Electronics, which provides the technology for Aarhus Water, the municipal water utility.

The plant generates energy from the biogas it creates out of household wastewater, including sewage. Carbon is extracted from the wastewater and pumped into digesters kept at 38掳C filled with bacteria. These produce biogas 鈥� mostly methane 鈥� that is then burned to make heat and electricity.

鈥淲e don鈥檛 add any extra organic material like from restaurants or energy from wind turbines or solar panels,鈥� says Lars Sch酶der, general manager of Aarhus Water.

The technology isn鈥檛 new. But its success in Aarhus is down to a combination of strict environmental regulations targeting water discharge and a mandate for reducing nitrate and phosphate pollution. Tailored infrastructure for using the recovered energy has helped, as has controlling the daily and seasonal pressure on the pipes, which greatly reduced money lost due to leaks and maintenance costs.

Upgrading the facilities in Marselisborg required an upfront investment of nearly 鈧�3 million, but Aarhus Water expect that to be recouped in just five years, from maintenance savings and the sale of excess energy into the grid and the district heating system.

Other cities in Denmark, including Copenhagen, have been trying to copy the example of Aarhus, with interest from as far away as Chicago and San Francisco.

Energy efficiency

鈥淩eplicating Denmark鈥檚 experience and performance will not be easy,鈥� says Molly Walton, energy analyst at International Energy Agency.

The use of energy in the water sector is seldom simply quantified, Walton says. And energy efficiency is rarely in the picture, especially as it requires upfront investment that could considerably increase the price of the water.

Moreover, to work, the wastewater plant needs to be big enough to generate sufficient biogas, and even the wastewater has to be the right mix 鈥� if it鈥檚 diluted by storm or groundwater it will be more difficult to recover energy.

According to IEA鈥檚 World Energy Outlook 2016, the amount of energy used in the water sector will more than double over the next 25 years. As the global population grows, the water service will slowly expand requiring more energy to run, especially in developing countries.

With rising global temperatures, energy will be needed to provide fresh water from other sources such as desalinating seawater in more arid areas.

Kata Kar谩th鈥檚 trip to Aarhus has been paid for by Danfoss Power Electronics

Saving a species from extinction can be a back-breaking task.听Hungarian conservationists found this out last week when they started to dig out Vojvodina mole rats one by one听as part of an effort to relocate them to safety.

鈥淭his is a very rare species, only around 400 individuals left in the world,鈥� says S谩ndor Ugr贸, director of the Kiskuns谩gi National Park in Hungary. 鈥淭hey are actually much rarer than the well-known symbol of conservation the giant panda.鈥�

鈥淎fter the Iberian lynx or the Mediterranean monk seal, they are one of the rarest animals in Europe,鈥� says G谩bor Csorba, head of the Hungarian mole-rat protection committee, which advises the government.

The species (Nannospalax leucodon montanosyrmiensis) is only known to inhabit Hungary and the province of Vojvodina in northern Serbia.听But their populations are now under two-pronged threat (see video below).

One of the in Hungary lives in an area just outside the Kiskuns谩gi National Park that could soon be the site of a new solar power plant.听The other lives in an area along the Hungarian-Serbian border, where last year the Hungarian government erected a fence to deter refugees from entering the country, inadvertently blocking movement of wildlife, too.

The fence could physically isolate the mole rat population living around the border, and 鈥渨ill speed up its extinction鈥�, the Institute for Nature Conservation of Vojvodina Province.听The fence has effectively split their population in half, and the increased border control traffic may also be affecting the mole rats.

鈥淚t鈥檚 difficult to study these animals, we don鈥檛 know for sure how much the increased traffic from increased border control affects them 鈥� but we can鈥檛 afford to lose any,鈥� says Ugr贸.

So conservationists at Kiskuns谩gi decided to take some of the animals from the border area to establish a third Hungarian population in a safer location near the village of 脰tt枚m枚s.

鈥淚t is extremely hard to find a suitable habitat for these animals; this one took us a year to locate,鈥� says Csorba. The species requires a very specific type of soil, climate and vegetation, which is often already under cultivation.

Mole rats are not easy to catch, either. Rangers open the entrance of fresh molehills with a spade and have to avoid accidently injuring the animal as they block their escape with the spade.听The rangers insert a piece of reed near the entrance, which shakes when the animal comes up to plug the entrance (mole rats don鈥檛 like draft), indicating when to dig.

鈥淭his is also a unique opportunity to study the formation of a new population from the very beginning,鈥� says Attila N茅meth mole-rat expert at Kiskuns谩gi. 鈥淓very animal got a microchip, a health check-up and we took DNA samples.鈥�

To give them a good start, rangers have already built an artificial burrow half a meter below the surface for each of the seven individuals they have managed to relocate so far. Initially, rangers will regularly check on the animals until they are sure they are thriving in their new home.

Meanwhile,听conservationists are lobbying the government to restrict development of the solar plant on the site of the largest mole-rat population to just 5 hectares instead of the 130 hectares that had originally been proposed.听And they hope the site might be protected as part of the national park, but that probably won鈥檛 happen for another few months.

Read more: Naked mole rats reveal why they are immune to cancer

听

There are only around 60 vaquitas left, and it is now up to China whether the world鈥檚 smallest porpoise will escape extinction. That鈥檚 according to a report by campaign organisation the Environmental Investigation Agency (EIA).

The critically endangered porpoise is only found in the Gulf of California, where it often gets tangled in gill nets targeting the totoaba, a similarly sized fish that is also endangered and whose fishing and international trade are banned.

The totoaba鈥檚 swim bladders, known as 鈥渁quatic cocaine鈥�, are sought for their putative medical effects, and can fetch tens of thousands of dollars in China.

This trade still thrives there, despite a fall in prices and the ban, according to an investigation by the EIA.

鈥淭he totoaba trade is just not high priority for the Chinese authorities,鈥� says Clare Perry, head of the agency鈥檚 Oceans Campaign. 鈥淥pen illegal trade in Chinese markets clearly shows the lack of enforcement.鈥�

EIA has monitored the market, including online trading, since April 2015, and conducted undercover investigations in Hong Kong and other parts of southern China.

Posing as investors, the agency鈥檚 investigators identified the coastal town of Shantou, in Guangdong province, as the centre of the trade.

The investigations also found that traders in the port city of Guangzhou have become more wary as a result of local enforcement efforts, with bladders moving from being openly sold in 2015 to only being offered under the counter this year. In contrast, the bladders were still openly on sale in Shantou this June.

The report identified only two publicly reported seizures of totoaba bladders, both in Hong Kong.

And despite their price having plummeted thanks to oversupply in the past few years, this may not last.

Traders have begun hoarding their stocks 鈥� sometimes as many as 1000 dried bladders each 鈥� until prices climb again, says the EIA鈥檚 report. And even today, a bladder weighing half a kilogram can sell for as much as听$51,000.

The solution to saving the vaquita is most likely to involve ending China鈥檚 taste for the swim bladders.

鈥淚t is really clear what we have to do,鈥� says Perry, who hopes a meeting of the Convention on International Trade in Endangered Species later this month will put more pressure on China and help coordinate the international effort to save the species.

There have been some positive moves recently. At a between Mexico and the US, the Mexican government promised to ban from this month the use of gill nets where vaquitas are found. Both countries also promised to increase enforcement efforts to halt the illegal totoaba trade.

And China agreed at a June 2015 with the US to crack down on the trafficking of at-risk species such as totoaba.

Whether any of this materialises remains to be seen.

鈥淢辞蝉迟 traders and buyers aren鈥檛 even aware of the connection between the two species,鈥� says Perry. 鈥淚f we don鈥檛 stop the illegal trade, this will be a dual extinction.鈥�

Read more: World鈥檚 smallest porpoise, the vaquita, may be extinct by 2022

Every scar tells a story. Whales migrating through tropical waters often carry crater-like wounds, and cookie-cutter sharks looked like the culprits. But we lacked data on how frequent such attacks by sharks on whales might be, and where and when they happen.

Nicknamed 鈥渄emon whale biters鈥�, these elusive sharks usually lurk in warmer waters between latitudes 40掳 north and 40掳 south 鈥� corresponding to the zone between the Bahamas and Madagascar.

They are thought to rise up from depths of 1000 to 4000 metres to prey on fresh meat, taking chunks out of live whales 鈥� quite an undertaking given they are only around half a metre long.

鈥淭hat鈥檚 one of the ways they feed, taking non-fatal bites from much larger animals,鈥� says of Florida International University in Miami.

Now, two South Africa-based researchers have analysed wound data from more than 1700 whale carcasses collected by one of them at Donkergat whaling station in South Africa over 8 months in 1963, when commercial whaling was still allowed.

The characteristics of wounds seen in sei, fin, Bryde鈥檚 and sperm whales confirms that cookie-cutters (Isistius species) are indeed to blame.

鈥淭he fact that the animals were dead allowed us to inspect the whole body of the whale, not just the sections that are visible when the animal surfaces to breathe,鈥� says study co-author of the Centre for Statistics in Ecology at the University of Cape Town, South Africa. This meant they could look at where on a whale the bites occur, and the stage of would healing of the wound indicated when the attacks happened.

Dozens of wounds

The results show that the sharks inflicted many wounds from head to tail on whales passing through their habitat. One sei whale carried 138 unhealed bite marks.

Combining this with what we know about whale and shark distributions allowed the researchers to deduce how the frequency and timing of bites was related to whale migration.

鈥淲e found that whales are bitten regularly during the [southern hemisphere] autumn, winter and early spring,鈥� says Photopoulou. This indicates that by mid-spring the whales had migrated away from the zone where the sharks live.

The results tally with what we know about sei and fin whale migrations, but also reveal something new about sperm whales. The lower number of fresh wounds on maturing sperm whales suggest that they spend less time at lower latitudes 鈥� where the sharks are 鈥� than mature whales.

Papastamatiou says the study convincingly fingers cookie-cutter sharks as having caused the whale wounds. Given that there are often no other ways to study elusive deep-water creatures such as these sharks, he says, studying bite marks could also help refine our knowledge of the sharks鈥� distribution.

Although the era of whaling in South Africa is long gone, 鈥渄emon bitten鈥� scars on living whales can offer new insights into the behaviour of lesser-known whale species, too, Photopoulou says.

Read more: The enigmatic whale we can hear 鈥� but have never seen; Sharks seen hunting and killing a whale for the first time