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Showing posts with label Animals. Show all posts
Showing posts with label Animals. Show all posts

Sunday, 26 January 2020

Four new species of walking sharks discovered in Australia

The vast majority of sharks swim to move around, but some specific species can use more unique means of transport. This is the case of walking sharks, that is to say sharks using their fins as limbs to move on the seabed. And recently, four new species of walking sharks have been discovered by Australian marine biologists.

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Unlike their larger cousins, members of these newly discovered species of walking sharks spend their time wandering gently along coral reefs on four flat fins. Or, at least, that's what they were doing when the researchers spotted them in the shallow waters of northern Australia.

In an article published in the journal Marine & Freshwater Research , marine biologists declared that the four new itinerant shark species were the most recently evolved shark species known, having developed after having separated from their common ancestor on closer about 9 million years ago.

Walking sharks: unique characteristics for a definite evolutionary advantage

" With an average length of less than one meter, walking sharks pose no threat to humans, but their ability to withstand oxygen-poor environments and to walk on their fins gives them a remarkable advantage over their prey, small crustaceans and molluscs ”explain the researchers.

Walking sharks have unique characteristics compared to their closest relatives. Credit: Mark Erdmann

These unique characteristics are not shared with their closest relatives, whip sharks, or more distant relatives in order of carpet sharks, including whale sharks. The four new species almost doubled the total number of known walking sharks, bringing the total to nine. the researchers said they live in the coastal waters of northern Australia and the island of New Guinea and occupy their own separate region.

Better understand the evolution of walking sharks

“ We estimated the link between the species on the basis of comparisons between their mitochondrial DNA which is transmitted through the maternal line. This DNA codes for mitochondria, which are the parts of cells that convert oxygen and nutrients from food into energy for cells . ”

The data suggest that the new species evolved after sharks moved away from their original population, became genetically isolated in new areas, and developed into new species.

This video shows a walking shark moving on the ocean floor:


Walking, swimming or hitching a ride? Phylogenetics and biogeography of the walking shark genus Hemiscyllium

Christine L. Dudgeon A H , Shannon Corrigan B , Lei Yang B , Gerry R. Allen C , Mark V. Erdmann D E , Fahmi A F , Hagi Y. Sugeha F , William T. White G and Gavin J. P. Naylor B

Marine and Freshwater Research

Monday, 9 December 2019

How do rats use empathy to prepare for danger?

Many studies have shown the tremendous abilities, individual or societal, of rats. They are able to solve basic puzzles, organize themselves into hierarchical colonies and perform complex tasks. They also manage to avoid danger in a particularly effective way. And researchers at the Netherlands Institute of Neuroscience have finally discovered a key element in this mechanism: empathy. Indeed, by recognizing and feeling the fear and emotions of their fellow creatures, rats know when to avoid an immediate danger.

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Their study shows that rats can use their siblings as antennas signaling danger, being extremely sensitive to the emotions of the rats that surround them. With this discovery, new targets for the treatment of empathic disorders in humans, such as psychopathy and frontotemporal dementia, could be identified in the future. The study was published in the journal PLOS Biology.

Preparing for danger through empathy

Contrary to the idea that empathy is one-way, where one person shares the pain of another, researchers have discovered a more interactive process in which animals align their emotions with mutual influences. They put two rats face to face, then surprised one of them (the demonstrator) with a brief electrical stimulation of the paws. They then observed the reaction of the two rats (the other being the viewer).

When a rat shows a reaction of fear, the other rat also feels it. In return, the reaction of the second conditions the fear felt by the first. Credits: Yingying Han et al. 2019

"The first thing we observed is that when you see your neighbor jump, the viewer is suddenly scared too. The viewer feels the fear of the demonstrator, "explains Rune Bruls. The spectator's reaction influences the way the demonstrator feels the shock. The spectators who were less afraid reduced the fear of their demonstrators. " The fear goes from one rat to another. In this way, a rat can prepare for danger before he even sees it . "

An empathic process similar to that of humans?

In humans, attending to the pain of others activates an area between the two hemispheres that is also active when we feel pain within our own body. This is considered one of the main areas of empathy of the brain. To see if this region is the same in the rat, the team injected a drug to temporarily reduce activity in this area.

"What we observed was striking: without the region that humans use to show empathy, the rats were no longer sensitive to the distress of another rat. Our sensitivity to other people's emotions may be more like that of the rat than many thought, "explains Keysers.

An empathy independent of the familiarity of individuals

The study also revealed that empathy is independent of whether or not to know the individual. For the rats that had never met, the emotions of the other rat were as contagious as for the rats that had shared the same "house" for 5 weeks. " It really challenges our notions about the origin of empathy, " explains Valeria Gazzola.

Familiarity between individuals does not influence the ability of rats to be empathic. They show empathy for both familiar and unknown individuals. Credits: Yingying Han et al. 2019

Many believe that humans and animals are empathic because they are sensitive to the suffering of their offspring. This parental concern then spreads to empathy for the closest friends. " What our data suggests is that an observer shares the emotions of others because it allows the observer to prepare for danger. It's not about helping the victim, but about avoiding becoming a victim yourself, "says Gazzola.

A level of empathy depending on past experiences

Although familiarity with the demonstrator plays no role in a rat's empathic or non-empathic reaction, previous experience does. Efe Soyman compared two groups of observers: one who had experienced electrical stimulation in the past and one who had not. He found that while experienced observers showed high levels of empathic fear, the inexperienced ones barely responded to what had happened to the demonstrator.

This is important because it shows that emotional contagion is not an innate mechanism, but something we must learn. " Rats are like humans: the more our experiences match those of the people we observe, the more we can understand how they feel, " Soyman concludes.


Bidirectional cingulate-dependent danger information transfer across rats

Yingying Han, Rune Bruls, Efe Soyman, Rajat Mani Thomas, Vasiliki Pentaraki, Naomi Jelinek, Mirjam Heinemans, Iege Bassez, Sam Verschooren, Illanah Pruis, Thijs Van Lierde, Nathaly Carrillo, Valeria Gazzola, Maria Carrillo, Christian Keysers

PLoS Biol 17(12): e3000524.


Wednesday, 4 December 2019

Sperm whale found dead on Scottish coast with 100 kg of waste in stomach

With the rise of human industrial activities, ocean pollution has grown steadily in recent years, including plastic pollution whose signs are now visible in all oceans and seas of the world. The first victims of this situation are marine animals ingesting plastic waste. Many stranded marine mammals have, in recent years, been found with alarming amounts of objects in their stomachs. But recently, it is a new sinister record that has been established on the Scottish coast, where a sperm whale has been found with 100 kg of various waste in the stomach.

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The young sperm whale ( Physeter macrocephalus ) ran aground on November 28 at Luskentyre Beach, Scotland, in the Outer Hebrides Islands. He died shortly after. Fishing nets, ropes, tubes and an assortment of plastic wastes formed a compact mass inside the 20-tonne animal, and some appeared to have been there for some time.

The skin and fat of the whales isolating them so effectively, the bacteria inside a corpse of whale can multiply quickly, even when the temperature of the air is low. While bacteria help decompose leftovers, they produce gases that build up pressure inside the body, and the sperm whale on the Scottish beach was no exception.

After having naturally opened in two under the effect of internal gases, the sperm whale's body revealed 100 kg of various waste: ropes, nets, plastic bags, etc. Credits: SMASS

He "somehow exploded" during the examination of his corpse. " By the time we got near the corpse to look at it, the sperm whale had been dead for 48 hours and most of the guts were blown when we put a knife in, " writes a SMASS representative.

To better understand coastal strandings of marine animals

SMASS researchers and volunteers collect and analyze data on stranded animals along the Scottish coast, which includes 790 islands and stretches 19,000 kilometers. By performing necropsies and studying the remains of failed marine life - sharks, porpoises, dolphins, sea turtles and seals, as well as whales - scientists can better understand the biological and environmental conditions that lead to stranding.

While the amount of waste inside the whale was impressive, the animal appeared to be in good health and not malnourished. It is likely that the scoop of ball was a hindrance to digestion, but SMASS experts found no evidence that ingested debris was blocking the whale's intestines.

Plastic pollution: a deadly global danger for all marine animals

Other sinister examples of dead whales with belly full of plastic that have been stranded on the coasts of other countries exist. A pregnant sperm whale that floated on an Italian beach in April, died with 22 kg of waste in its stomach, and a Cuvier's beaked whale that arrived in the Philippines in March had swallowed 40 kg of waste. Sperm whales that were stranded in 2018 in Spain and Indonesia also had indigestible masses in their belly.

Large marine mammals are not the only ones to suffer from ocean pollution. Here is a photo of Emily Mirowski, a marine biologist at the Gumbo Limbo Center, performing the autopsy of a turtle. You can see the pile of plastic pieces extracted from his stomach next to it. Credits: Gumbo Limbo Nature Center

In the United Kingdom, stranded marine animal bodies usually have microplastic particles in their bodies, although it is unclear how this affects their overall health. But animals stranded with large amounts of debris in the belly are rare in the British coast. In the recent grounding, the garbage assortment in the whale's gut highlights the global problem of widespread marine pollution caused by various human activities.

Tuesday, 3 December 2019

For the first time, the heartbeat of the blue whale has been recorded

With a length of up to 30 meters and a mass of up to 170 tonnes, the blue whale is currently considered to be the largest living animal and possibly the oldest living on Earth. To assume the physiological needs of such a template, the heart of the blue whale must be strong enough. Although marine biologists already knew that the animal's heart rate changes relatively quickly as it dives for food, they were surprised to find out how much. Indeed, during a dive, the heart of a blue whale goes from about 30 beats per minute to only 2.

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This is what a team of marine biologists discovered after recording for the first time the heartbeat of a blue whale. After placing a pulse monitor on a blue whale off the California coast, the researchers watched the gigantic creature sink and return to the surface for nearly 9 hours, alternately filling her lungs with air and her belly with hundreds of Pisces.

A heart with rapid variations to ensure physiological needs

During these deep foraging dives, the whale's heart rate changes abruptly, going up to 34 beats per minute at the surface and only two beats per minute in the deepest waters - which is about 30 at 50% slower than the researchers expected.

According to the new study published in PNAS , the mere fact of catching prey could push the heart of a blue whale into its physical limits - which could explain why no larger creature than the blue whale has ever been spotted on Earth.

" Animals that work at physiological extremes can help us understand the biological limits of size, " says Jeremy Goldbogen, a marine biologist at Stanford University. In other words: If the heart of a blue whale could not pump faster to feed its daily foraging expeditions, how could the heart of a larger animal pump even faster for more even bigger energy?

A slow heart rate during the dive

Blue whales are the largest animals ever to have lived on Earth. As adults, they can be more than 30 meters long, about the size of two school buses parked end-to-end. It takes a big heart to propel a creature of this size. The heart of a blue whale can weigh up to 180 kg (2015 failed specimen), about the size of a golf cart.

Scientists already knew that the pulse of a blue whale had to slow down deeply. When air-breathing mammals dive underwater, their bodies automatically begin to redistribute oxygen; the heart and brain receive more O2, while muscles, skin and other organs absorb less O2. This allows the animals to stay underwater longer with a single breath, resulting in a significantly lower heart rate than normal.

Graphs showing heartbeat variations of the blue whale as a function of depth and position of the animal. Credits: JA Goldbogen et al. 2019

This is true for humans as well as for blue whales. However, given the gigantic size of the whale and its ability to dive more than 300 meters deep, their hearts are pushed to limits far beyond ours. To find out exactly how much a blue whale's heart rate changes during a dive, the authors followed a group of whales they had previously studied in Monterey Bay, California, and fixed a special mounted sensor at the end of a 6 m pole on one of them.

A cardiac transition from 30 to 2 beats per minute

The studied whale was a male first sighted 15 years ago. The sensor was equipped with a plastic shell the size of a lunch box, equipped with four suction cups, two of which contain electrodes to measure the heart rate of the whale.

The researchers set the monitor on their first attempt, and he stayed there for 8½ hours when the whale dipped and resurfaced during dozens of foraging "missions".

Most of this time was spent underwater: the whale's longest dive lasted 16.5 minutes and reached a maximum depth of 184 m, while it never spent more than 4 minutes on the surface to fill the lungs. The sensor showed that, deep within each dive, the heart of the whale beat on average four to eight times per minute, with a minimum of two beats per minute.

Graphs showing the heart rate of the blue whale according to its lung volume and depth. Credits: JA Goldbogen et al. 2019

Between these low-tempo beats, the stretched aortic artery of the whale slowly contracted so that the oxygenated blood slowly moved into the body of the animal. Back on the surface, the whale's heart rate accelerated to 25 to 37 beats per minute, which quickly loaded the animal's bloodstream with enough oxygen to support the next deep dive.

The biggest heart on Earth

During these quick stopovers, the heart of the whale skirted its physical limits - it is unlikely that the heart of a whale could beat faster than that. This natural heart limit may explain why blue whales reach a certain size and why no known animal on Earth has ever been so tall.

Since a larger creature would need more oxygen to support its long, deep dive for food, his heart would need to beat even faster to get oxygen back to the surface. According to the authors of the study, this does not seem possible on the basis of current data.

Video presenting the work done by the researchers:


Extreme bradycardia and tachycardia in the world’s largest animal

ORCID ProfileJ. A. Goldbogen, ORCID ProfileD. E. Cade, J. Calambokidis, M. F. Czapanskiy, J. Fahlbusch, A. S. Friedlaender, W. T. Gough, S. R. Kahane-Rapport, M. S. Savoca, K. V. Ponganis, and P. J. Ponganis

PNAS first published November 25, 2019

Sunday, 1 December 2019

Equipping the cows with a virtual reality headset could make them produce better milk

Apparently, the virtual reality is not just for humans ... According to a new Russian experience to say the least unusual, cows wearing a VR helmet displaying virtual environments and stimulants would be in a better mood, and thus would produce a better milk quality.

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Farmers in the Moscow region have placed modified VR (virtual reality) helmets on cows to determine whether such visual (and sonic) stimulation would improve their mood and, consequently, their milk production.

As part of the study project, the livestock benefited from a realistic 3D model of a field, with colors adapted to the animals' eyes, thus offering them a landscape much more pleasant than their confined space within a closed. The helmets have been adapted to the structural features of the cow heads so that they can see properly.

Collaboration between farmers, developers and veterinarians

The technique, proposed by Russian farmers in collaboration with developers and veterinarians, seems to have worked, at least in terms of cow mood.

The first test, conducted on a farm in Krasnogorsk, northwestern Moscow, reduced cow anxiety and increased their overall sense of well-being. Although it is not yet certain that this affects the quality or volume of milk production, a more "comprehensive" study is planned to answer this question.

However, this experience raises some questions: Why not just leave the cows more often in the fields? Is there a risk of disturbing the animals when their helmet has to be removed (for maintenance or changing the battery for example), thus temporarily revealing the sad reality hidden to them?

In a way, it is a solution to a problem created by Man ... But it is equally obvious that this could be considered as an "option" for farms that do not have enough (or at all ) open fields, or for which existing techniques (such as playing nice music) may not be effective.

System developers, meanwhile, plan to extend the VR experience if observations continue to show positive results.


Saturday, 9 November 2019

Ants trapped for years in a bunker survived in an absolutely terrible way

In the woods of western Poland is a Soviet nuclear base dismantled, which includes two underground bunkers in which nuclear munitions were once kept ... After the military complex was abandoned, these strange artificial grottoes became resting places for them. overwintering bats.

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In the early 2010s, volunteers began to visit these bunkers to monitor the bats population in winter, and discovered a different type of inhabitant ...: a huge mass of wood ants ( Formica polyctena ) trapped on the floor of the bunker, survivor without a queen nor any of their usual comforts. So how did these creatures survive without light and without food ...?

When it was discovered in 2013, this "colony" of underground ants already had about a million living workers and several million dead ... Namely that they did not reproduce: instead, the population had been reconstituted by accident .

The ant colony of the bunker, with a real "cemetery" against the back wall. Credits: Wojciech Stephan / Czechowski et al./Journal of Hymenoptera Research

In the ceiling of the bunker was a rusty ventilation duct, connecting the dark room to the forest above. A colony of giant ants had built a mound on the ground just above the bunker vent, and as the metal rusted, part of their ranks began to fall into the concrete cavern below. ...

The ventilation pipe located on the ceiling of the bunker. Credits: Rutkowski et al./Journal of Hymenoptera Research

The study of the limits of the living conditions of ants is of great interest to some entomologists. For several years, researchers have visited the bunker several times and watched with fascination as this isolated population continued to grow and survive despite a clear lack of light, heat and food.

Now scientists finally know how these trapped insects managed to survive: the mass consumption of their own imprisoned nestmates ...  Cannibalism was suspected by the researchers: you should know that these ant-woods are, after all, the the only major source of food available in this restricted area, other than occasionally dead mice or bats. Moreover, it is known that this particular species consumes its own fallen dead in territorial " ant wars ", and when food is scarce.

To confirm this intuition, a team of researchers collected the bodies of several ants, scattered in the bunker. Looking closely at 150 dead workers, the team found that the vast majority of bodies (about 93%) had holes (as gnawed) and bite marks.

Scientists confirm that these are obvious signs of mass consumption, with virtually no other body in the bunker able to leave these marks.

" The survival and growth of the bunker 'colony' over the years, without producing its own offspring, has been possible thanks to a continuous supply of new workers from the upper nest and an accumulation of corpses,  " concluded the researchers. "  The corpses were an inexhaustible source of food, which allowed the survival of the trapped ants under otherwise extremely unfavorable conditions,  " they added.

The colony built above the ventilation pipe. Credits: Czechowski et al./Journal of Hymenoptera Research

According to the results of the researchers, it seems that the wood ants can face a remarkable adversity to survive. But, fortunately for this colony, the individuals the populated are no longer obliged to fend for themselves: in 2016, the researchers installed a wooden ramp (which can be seen in the image below) in the bunker, connecting the ventilation pipe to the ground. After four months, almost all the trapped ants had deserted the floor of the bunker.

Here is the help given to the ants trapped in the bunker (a simple piece of wood, allowing them to get out of the bunker of death ...). Credits: Rutkowski et al./Journal of Hymenoptera Research

Indeed, now, ants that have the misfortune to fall into the dark bunker, will no longer be forced to resort to cannibalism to survive. They can simply go out and go quietly to their occupation on the surface, in the open air, with their companions.


Wednesday, 6 November 2019

The decline of insect populations over the last decade has been largely underestimated

For several years, biologists have noted a continual decline in insect populations around the world, linked to the disappearance of certain biospheres and the alteration of ecosystems by human activities, particularly the intensification of agriculture and deforestation. . However, a new large-scale study reveals that the magnitude of this decline in insect populations over the last decade has been largely underestimated.

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In a large-scale biodiversity study, an international team of researchers found that insect species in forests and grasslands in Germany had decreased by about a third. And this only in the last decade.

" A decline of this magnitude over a period of just 10 years has completely surprised us, " said Wolfgang Weisser, ecologist at the Technical University of Munich (TUM). " It's scary, but it's the picture in a growing number of studies ."

Between 2008 and 2017, the research team collected more than one million insects from 300 sites in Germany. Of the approximately 2700 species studied, many appear to be declining. In fact, the team said that in recent years, some rare insects have never been found.

A significant drop in insect populations in the grasslands

No matter where the researchers looked, the conclusion was the same. From pastures for sheep to grasslands to forests, the team reported significant losses in insect diversity, and the largest losses were in grasslands, particularly those surrounded by farms.

In this type of environment, insect abundance decreased by 78%, while biomass dropped by 67%. The loss of insects in German meadows has already been demonstrated, but never in such detail. Most of the previous studies focused only on biomass, the total weight of all insects, not the number of species present.

The researchers found a significant decline in the abundance of insect species. Rare species disappear in favor of more common opportunists. Credits: Sebastian Seibold et al. 2019

" The fact that a large part of all insect groups is actually affected has not yet been demonstrated. Before our survey, it was unclear whether and to what extent forests were also affected by the decline of insects, "says TUM ecologist Sebastian Seibold.

Forest environments also affected

In forest areas, biomass has decreased by 40% and the number of species has decreased by a little over a third. According to the team, those who suffered the most were insects that covered long distances. Although this may be due to decimated forests, further research will be needed to determine the cause.

Although the decline in biomass, abundance and number of insect species is higher in grasslands (blue), forests are also affected by these extinctions (orange). Credits: Sebastian Seibold et al. 2019
" Our results show that there is a general decline in biomass, abundance and number of arthropod species across trophic levels. The decline of arthropods in forests shows that loss is not limited to open habitats, "the researchers write.

Rare insects replaced by opportunistic species

Additional research will be needed to obtain a complete picture of these changes in biomass, abundance and diversity - but the data contains some clues. The losses in the German grasslands were the highest among the rarest insects, which could explain to a large extent the alarming numbers.

In the forests, on the other hand, the scenario is different. Here, the biomass of insects has remained relatively constant over 10 years. In fact, the most abundant insects have become even more ubiquitous. This suggests that when insects disappear in forest environments, they are quickly replaced by other, more opportunistic species.

Identify the specific causes of insect decline

In the most catastrophic scenario, some entomologists warned that insects could disappear within a century; others believe that it is more likely that a small number of species will survive by taking advantage of the loss of competitors.

The authors did take climate change into account, but these were beyond the scope of this study. Not everyone is convinced that climate change is the main factor in the loss of insects, but there is good reason to believe that it could help.

" Although the factors of arthropod decline in forests remain unclear, in grasslands these factors are associated with the proportion of agricultural land in the landscape. However, we can not determine whether the observed declines are caused by the effects inherited from historical intensification of land use or by the recent intensification of agriculture at the landscape level.


Saturday, 26 October 2019

Monkeys were caught eating rats in a palm oil plantation in Malaysia

A macaque devouring a rat. | Anna Holzner
Pig-tailed macaques (family Cercopithecidae) feed mainly on sweet fruits and other vegetables. But, to the surprise of the scientists who made this intriguing discovery, they can also eat an astronomical amount of ... rats. Indeed, macaques were caught eating rats in a palm oil plantation in Malaysia.

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The researchers found that, far from being seen as pests, monkeys could ultimately be prime guests in Malaysian oil palm plantations, compensating more than the few fruits they steal by reducing a threat well. more important: rodents.

Over the last six years, scientists from Malaysia and Germany have closely monitored two populations of Pig-tailed Macaques (here in particular Macaca nemestrina) from the south of Segari Melintang Forest Reserve, Malaysia. The monkeys spent a lot of time relaxing in the palm oil plantation surrounding the reserve, which represents about one-third of their living area.

Farmers may not have been happy with the intrusion of monkeys, but for macaques, the palm oil plantation was like a supermarket: indeed, although monoculture encroaches on their habitat, it offers them "cheap" food. Note that these macaques spend several hours a day in the plantations, about half of their total feeding time. As a result, it is not surprising to see them busy eating palm fruit.

What was a little more surprising though, even shocking when scientists discovered it, is the main dish of macaques: rats. " I was stunned when I saw that macaques were feeding on rats in plantations, " says Nadine Ruppert, an ecologist at Universiti Sains Malaysia. " I did not expect them to hunt these relatively big rodents or eat so much meat. They are widely known to be frugivorous primates, which only feast on small birds or lizards from time to time  , "she added.

An adult male pigtailed macaque consuming a rat in oil palm plantations. Credits: Anna Holzner
This observation leads to interesting questions: Are monkeys really the enemies of farmers? Is their presence a lower cost for them, since they perform a service for the least practical fight against rats? Why do these monkeys eat so many rats?

Through their research, scientists have found that monkeys eat more than 12 tons of palm fruit a year. It may sound like a lot, but you should know that this amount is only a little over half a percent of the total production of the plantation area covering their home range ... This is nothing compared to the damage caused by rats, which they can potentially nibble up to 10% of the products of the plantation.

Of course, if the monkeys ate only a few rats from time to time, it certainly would not make a big difference. But it turns out that they can consume very large quantities ... " In discovering cavities in oil palm trunks, where rats seek refuge during the day, a group of pig-tailed macaques can capture more than 3000 rats a year!  Said Anna Holzner, an anthropologist at the University of Leipzig, Germany.

As a result, if a primate-hungry population feeds on rats that cause havoc on the plantations, their damage could be reduced to only 2% (instead of 10%). Of course, there is still the 0.56% damage caused by the monkeys. But the total would represent a loss of less than 3%, which is always more advantageous than the 10% caused only by rats ...

However, in this calculation, one must also consider ethics. Indeed palm oil plantations are important activities in Southeast Asia, but their cost to the environment is more than considerable.

As a result, finding ways to turn these plantations into non-hostile areas for the surrounding wildlife could help to save, in part, the industry's terrible reputation for its impact on wildlife.

" We hope that our results will encourage private and public plantation owners to consider protecting these primates and their natural forest habitat in and around existing and newly established oil palm plantations ," said Anja Widdig. , lead author of the study, also from the University of Leipzig.