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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:




Bibliography:

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

https://doi.org/10.1071/MF19163

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.


Bibliography:

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.

doi:10.1371/journal.pbio.3000524

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:



Bibliography:

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

https://doi.org/10.1073/pnas.1914273116

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.



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