Hexbyte Glen Cove Scientists learn how otters stay hotter thumbnail

Hexbyte Glen Cove Scientists learn how otters stay hotter

Hexbyte Glen Cove

A sea otter sits on a chunk of ice that fell from a glacier in the Prince William Sound near Whittier, Alaska.

Sea otters are a hardy lot.

The smallest of all marine mammals with the thickest fur of the animal kingdom, they can hold their breath for up to eight minutes while they dive for prey like clams and crabs, which they’re known to crack open using rocks.

An enduring mystery, however, was just how the mustelids manage to stay warm in the chilly waters of their Pacific habitat, bereft of the blubber that insulates seals, whales and walruses.

The answer, according to a new paper published in the journal Science on Thursday, is their bodies have a unique energy conversion system whereby their “leaks” heat throughout their bodies.

That’s unlike other mammals, which have to put their muscles to work through exercise, or involuntary shivering, to achieve the same result.

Lead author Traver Wright of Texas A&M University told AFP that while ‘ dense, water-resistant fur offsets some , it isn’t enough by itself to cope with the frigid waters off Alaska, where most of them reside.

Scientists already knew the sea otters burn a lot of energy—approximately three times greater than predicted for mammals of their size, and to keep up with the demand, they may consume up to 25 percent of their in a day.

Canadian sea otters swim on June 5, 2012 in the zoo of Amneville, eastern France.

It was unclear, though, which tissues were making use of this energy and how it was going towards producing heat.

To find out, Wright and colleagues took muscle samples from sea otters that were already dead, or, more happily, had been rehabilitated by the Monterey Bay Aquarium and were being prepared for release.

They then used a device to measure oxygen consumption.

‘Making heat by being inefficient’

The main function of muscles is generally to be able to move the body, but in the otters, much of the produced by breaking down sugars and fats was lost as heat instead of being used in the cells to do work such as powering muscle contraction.

“One of the interesting things that we found is that they’re really good at making heat by being inefficient,” said Wright.

What the team observed would be considered wasteful in land mammals like humans, “but if you’re an animal that’s trying to warm up, then that ‘wasted’ energy and is a good thing.”

Sea otters, the smallest of all marine mammals with the thickest fur of the animal kingdom, they can hold their breath for up to eight minutes while they dive for prey like clams and crabs, which they’re known to crack open using rocks.

In other words, ideal for helping maintain a body temperature of 37 degrees Celsius (98.6 degrees Fahrenheit) in freezing conditions.

The team found that this “thermogenesic” effect was present in sea otters from the time they were babies to adults, and there was no difference in captive and wild-raised animals.

Sea otters and marine mammals more broadly might have evolved such traits when their terrestrial ancestors began taking to the oceans 50 million years ago, but that hypothesis will require more research to confirm.

Learning how sea otters’ metabolic system functions differently from ours could one day also help humans solve obesity issues, added Wright.

“If you can figure out how to increase the leak and metabolic rate, you could theoretically have humans revving up the metabolism and burning off additional calories.”



More information:
T. Wright el al., “Skeletal muscle thermogenesis enables aquatic life in the smallest marine mammal,” Science (2021). science.sciencemag.org/lookup/ … 1126/science.abf4557

© 2021 AFP

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Scientists learn how otters stay hotter (2021, July 8)
retrieved 9 July 2021
from https://phys.org/news/2021-07-scientists-otters-hotter.html

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Hexbyte Glen Cove What can we learn from vanishing wildlife species: The case of the Pyrenean Ibex thumbnail

Hexbyte Glen Cove What can we learn from vanishing wildlife species: The case of the Pyrenean Ibex

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Laña, the last surviving Pyrenean Ibex, returned as a mounted animal to Torla-Ordesa on the 6th November 2012 after its controversial cloning attempt. Her skin is now exhibited in the visitors centre of Ordesa & Monte Perdido National Park Credit: Manolo Grasa

Likely the first extinction event of the 2000s in Europe, the sad history of the Pyrenean Ibex (Capra pyrenaica pyrenaica) is a powerful example of the ever-increasing species loss worldwide due to causes related to human activity. It can, however, give us valuable information on what should be done (or avoided) to halt this extinction vortex.

The distribution of this subspecies of Iberian Ibex was limited to the French and Spanish Pyrenees. Its first mention in an official written document, dating back to 1767, already refers to it as extremely rare. Like many other , it was almost hunted to before its killing became prohibited in 1913. Neither the institution of a national park (Ordesa & Monte Perdido), nor a conservation project with European LIFE program funding could stop the extinction of the Pyrenean Ibex eventually officialised on January 6, 2000. But the story of this charismatic animal did not end there—a controversial cloning program was started instantly with no scientific agreement, nor support from regional environmental NGOs, claiming that de-extinction was possible even in the absence of further DNA studies.

To find out more about the drivers of its extinction, an international team composed of 7 nationalities built a database of all known museum specimens and reconstructed the demographic history of the Pyrenean Ibex based on DNA evidence. Their research is published in the open-access, peer-reviewed journal Zoosystematics and Evolution.

Only the French mountaineer and photographer Bernhard Clos managed to take a series of good photos of the Bucardo, as the Pyrenean Ibex is called on the Spanish side. Credit: Bernhard Clos

The research found that after a between 14,000 and 29,000 years ago (which is quite recent from a genetic point of view), a significant loss of genetic diversity followed between approximately 15,000 and 7,500 years BP, and continued until present. By that time, the Pyrenean Ibex also lived outside the Pyrenean mountain chain, but, gradually, its distribution was reduced to only one valley in the Ordesa National Park in the Spanish Pyrenees.

Written sources confirm hunting of the Pyrenean Ibex from as early as the 14th century, and during the 19th and 20th century it became a common target for trophy hunters. Undoubtedly, hunting played an important role in reducing its and distribution area, but it is not possible—with the information currently available—to pinpoint it as the straw that broke the camel’s back. Infectious diseases that originate from livestock (for instance, those caused by the bluetongue virus, BTV, and sarcopses) are capable of decimating other subspecies of Iberian Ibex in extremely short periods of time.

The adventures of the British hunter E.N. Buxton were published in 1893. This engraving represents a hunting party in the Ordesa Valley (Spanish Pyrenees). Credit: Pensoft Publishers

While the relative contribution of various factors remains largely unknown, it seems that hunting and diseases transmitted from other animals have been effective in drastically reducing the number of Pyrenean ibexes over the last two centuries, because they were acting on an already genetically weakened population. This low genetic diversity, combined with inbreeding depression and reduced fertility, brought the population beyond the minimum viable size—from that point onwards, extinction was inevitable.

This case study shows the importance of historical biological collections for genetic analyses of extinct species. A privately owned 140-year-old trophy preserved in Pau, France, was genotyped as part of this research, showing that private individuals may possess material of high value. As there is little knowledge of such resources, the authors call for the creation of an online public database of private collections hosting biological material for the benefit of biodiversity studies.



More information:
Giovanni Forcina et al, Demography reveals populational expansion of a recently extinct Iberian ungulate, Zoosystematics and Evolution (2021). DOI: 10.3897/zse.97.61854

Citation:
What can we learn from vanishing wildlife species: The case of the Pyrenean Ibex (2021, April 6)
retrieved 6 April 2021
from https://phys.org/news/2021-04-wildlife-species-case-pyrenean-ibex.html

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part may be reproduced without the written permission. The content is provided for information purposes only.

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Hexbyte Glen Cove Dogs may never learn that every sound of a word matters thumbnail

Hexbyte Glen Cove Dogs may never learn that every sound of a word matters

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Credit: Vivien Reicher

Despite their excellent auditory capacities, dogs do not attend to differences between words that differ only in one phoneme (e.g., “dog” vs “dig”), according to a new study by Hungarian researchers of the Eötvös Loránd University, Budapest (ELTE). In the study, they measured brain activity with non-invasive electroencephalography (EEG) on conscious dogs. This might be a reason why the number of words dogs learn to recognize typically remains low throughout their life. The study is published in Royal Society Open Science.

Dogs can distinguish human speech sounds (e.g. “d,” “o” and “g”) and there are similarities in the neuronal processing of words between and humans. However, most of the dogs can learn only a few words throughout their lives even if they live in a human family and are exposed to human speech. Magyari and her colleagues hypothesized that despite dogs’ human-like auditory capacities for analyzing speech sounds, they might be less ready to attend to all differences between speech sounds when they listen to words.

To test this idea, the researchers developed a procedure for measuring in the noninvasively on conscious, untrained family dogs. Electroencephalography (EEG) is a common procedure in human clinical and research studies and it has been also successfully applied on tranquilized, sleeping or conscious but trained dogs. However, in this study, the researchers measured EEG on conscious dogs without any specific training.

The researchers invited dogs and their owners to the lab. After the dog became familiar with the room and the experimenters, the experimenters asked the owner to sit down on a mattress together with her dog to relax. Then, the experimenters put electrodes on the dog’s head and fixed it with a tape. The dogs then listened to tape-recorded instruction words they knew (e.g., “sit”), to similar but nonsense words (e.g., “sut”), and to very different nonsense words (e.g., “bep”).

Electroencephalography (EEG) is an often used technique in human clinical and research studies and it has been also successfully applied on tranquilized, sleeping or awake but trained dogs. However, in this study, the researchers measured EEG on awake dogs without any specific training. Credit: Elodie Ferrando

“The electroencephalography is a sensitive method not only to but also to muscle movements. Therefore, we had to make sure that dogs tense their muscles as little as possible during measurement. We also wanted to include any type of family dogs in our study, not only specially trained animals. Therefore, we decided that instead of training our dog participants, we will ask them just to relax. Of course, some of the dogs who came to the experiment could not settle down and did not let us do the measurement. But the from the study was similar to the dropout rate in EEG studies with human infants. It was also an exciting process for us to learn how we can create a relaxing and safe atmosphere in the lab for both the dogs and their owners,” says lead author Lilla Magyari, postdoctoral researcher at Department of Ethology, Eötvös Loránd University, Hungary.

The analysis of the recorded electric brain activity showed that dog brains clearly and quickly discriminated the known words from the very different nonsense words starting from 200 ms after the beginning of the words. This effect is in line with similar studies on humans showing that the human brain responds differently to meaningful and nonsense words already within a few hundred milliseconds.

But the dogs’ brains made no differentiation between known words and those nonsense words that differed in a single speech sound only. This pattern is more similar to the results of experiments with human infants who are around 14 months. Infants become efficient in processing phonetic details of words, which is an important prerequisite for developing a large vocabulary between 14 and 20 months. But younger infants do not process phonetic details of words in certain experimental and word learning situations despite the fact that infants are able to differentiate speech sounds perceptually within weeks after birth.

“Similarly to the case of human infants, we speculate that the similarity of dogs’ brain activity for instruction words they know and for similar nonsense words reflects not perceptual constraints but attentional and processing biases. Dogs might not attend to all details of speech sound when they listen to words. Further research could reveal whether this could be what incapacitates dogs from acquiring a sizable vocabulary,” says Attila Andics, principal investigator of the MTA-ELTE “Lendület’ Neuroethology of Communication Research Group.



More information:
Event-related potentials reveal limited readiness to access phonetic details during word processing in dogs, Royal Society Open Science (2020). royalsocietypublishing.org/doi/10.1098/rsos.200851

Provided by
Eötvös Loránd University

Citation:
Dogs may never learn that every sound of a word matters (2020, December 8)
retrieved 9 December 2020
from https://phys.org/news/2020-12-dogs-word.html

This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no
part may be reproduced without the written permission. The content is provided for information purposes only.