Author: MIL-OSI Publisher

Source: The Conversation – UK – By Kevin Healy, Lecturer in Macroecology, University of Galway

As you read this, the screen is probably flashing over 240 times per second, yet, as a human, you won’t notice this flickering light.

However, to a fruit fly hovering above your head, the screen would represent a strobe light fit for an Ibiza rave. This is because the way different species sample time, and the rates at which they can perceive it, varies greatly across the animal kingdom.

To us, a fast moving ball might seem like a blur but to dragonflies, pigeons and even bigclaw snapping shrimp it can be seen in great detail. But for species like snails or certain deep sea fish, like the escolar, the motion is probably too fast to register at all.

But why do animals perceive time differently?

To understand why, my colleagues and I collected published measures of time perception across the animal kingdom and analysed them. Our analysis showed this variation in time perception is largely driven by the pace of a species’s lifestyle.

Devices, such as electroretinograms, can measure time perception. The electroretinogram does this by recording the electrical activity of the retina in response to a flashing light. Gradually increasing the rate of flicker until the animal can no longer see the flashing can help scientists determine the limit of its time perception (scientists call this an organism’s maximum critical flicker fusion rate).

Our analysis showed that temporal perception has even greater variation than scientists may have realised. Our perceptual limit as humans is approximately 65 flashes per second. However, birds, such as the collared flycatcher, can see up to 138 flashes per second while tsetse flies and dragonflies can distinguish up to 300 flashes per second.

At 65 flashes per second (or Hz), humans display respectable temporal perception abilities compared to other animals. It is higher compared to many mammals, such as rats at 47 Hz, but slightly lower than dogs (84 Hz).

Our eyes seem even more respectable when compared to the slowest eyes in the animal kingdom, such as the deep sea fish, the escolar, which can only perceive 12 flashes per second or the most extreme cases of the crown-of-thorns starfish and giant African snail, both of which can only perceive 0.7 flashes per second.

But why does a dragonfly have such fast eyes while starfish are confined to a world of vision blur? One idea, called Autrum’s hypothesis, is that time perception costs a lot of energy and the evolution of such fast visual systems will only emerge in species with fast paced lifestyles.

Our analysis showed strong support for this idea, with the highest rates of temporal perception found in species which had behaviour that required fast reaction times. For example, animals that fly and predators which pursue their prey, like yellowfin tuna which can swim at over 70 kmph earning them the nickname of cheetah of the sea.

In contrast, the slowest rates of temporal perception were found in slower-moving species, such as the crown-of-thorns starfish which clock a top speed of 22 meters per hour.

We also found that in aquatic environments smaller species had faster vision. For example, while a one gram threespined stickleback fish can see at 67 Hz, a 350kg Leatherback can only see at 15 Hz. This finding supports previous studies which tested the idea that smaller, more manoeuvrable animals would also have faster temporal perceptions.

Although it is still unknown why this relationship is particularly strong in aquatic environments, it may be because water allows for more instantaneous movement.

Not all environments or lifestyles encourage the evolution of faster eyes. Our analysis also found that species in dimmer environments had much lower temporal perception abilities. For example, the giant deep sea isopod (which looks a bit like a giant woodlouse) can only see at 4Hz and the nocturnal tokay gecko can only see at 21 Hz.

This lower temporal perception is due to the need to capture every photon, light particle, available in darker environments. Similar to using slower shutter speeds with a camera, eyes with retinal cells that fire more slowly are better adapted at capturing the faintest objects. However, such adaptations to the dark come at the expense of temporal perception, and like a wobbly night time photo, are susceptible to motion blur.

So what does a second feel like to a dragonfly or to a snail? As Thomas Nagel outlined in his 1974 philosophical essay, What Is It Like to Be a Bat, we can never subjectively understand what the temporal perception of a dragonfly or snail feels like. However, by measuring the limitations of their sensory system we can grasp some sense of it.

A cup falling to the floor, a car speeding past on the street or a series of lightning strikes – for us humans, an event on the scale of a second is typically a blur, something we can just about register but not in much detail. But animals all process a different amount of visual information in a second. To us, a dragonfly may seem like Neo in the Matrix experiencing bullet time, seeing the world in slow motion.

And the extremely slow temporal perception of starfish of snails means their experience or the world is probably limited to a series of blurs.

Hence while a second may be physically the same for every organism on Earth, how you perceive it depends on how fast you live.

Kevin Healy does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.

– ref. Animals’ perception of time is linked to the pace of their life – new study – https://theconversation.com/animals-perception-of-time-is-linked-to-the-pace-of-their-life-new-study-275124

Source: The Conversation – UK – By Bethan Davies, Professor of Glaciology, Newcastle University

Rain is rare in Antarctica. Scientists doing fieldwork there dress for cold and glare, not wet weather – duvet jackets, snow trousers, goggles and sunscreen. Planes land on gravel runways which are rarely icy, since there is no precipitation to freeze. Historic huts remain well preserved in the dry air.

But this is beginning to change.

Rain is already falling more frequently on the narrow and mountainous Antarctic Peninsula, the northernmost finger of the continent pointing towards South America. Already the warmest part of Antarctica, the Peninsula is warming faster than the rest of the continent, and far faster than the global average. It provides an advanced sign of what coastal Antarctica – especially the fragile West Antarctic Ice Sheet – may experience in the coming decades.

I recently led a team of scientists looking at how the Antarctic Peninsula will change this century under three scenarios: high, medium and low greenhouse gas emissions. We found that, as the peninsula warms, precipitation will rise slightly – and will increasingly fall as rain rather than snow. As days above 0°C become more common, this rainfall will fundamentally change the peninsula.

When heat and rain arrive together

Extreme weather is already causing disruption. A heatwave in February 2020 brought temperatures of 18.6°C to the northern peninsula – T-shirt weather, for almost the first time in recorded Antarctic history – while the “ice shelf” surface alongside melted at a record pace.

Atmospheric rivers – long, thin corridors of warm, moist air that start at warmer latitudes – are playing a growing role. In February 2022, one resulted in record surface melt. Another, in July 2023, brought rainfall and temperatures of +2.7°C to the peninsula in the depths of winter. These events are happening more often, delivering rain and melt to regions where neither had been observed before.

What rain does to snow and ice

Snow does not like rain. We’ve all sadly watched snowfall melt away particularly rapidly when it rains.

On the Antarctic Peninsula, rain brings heat and melts and washes away snow, stripping glaciers of their nourishment. Meltwater can also reach the bed of the glacier, lubricating its base and making glaciers slide faster. This increases iceberg calving and the rate of glacier mass loss into the ocean.

On floating ice shelves, rain compacts the snow that has fallen on the surface, meaning water starts forming ponds. This ponded meltwater then warms, as it is less reflective than the surrounding snow and ice, and can melt downwards through the ice shelf to the ocean below, weakening the ice and causing more icebergs to break off.

This can destabilise the ice shelf. Meltwater ponding has been implicated in the collapse of the Larsen A and B ice shelves in the early 2000s.

Sea ice is vulnerable too. Rain reduces snow cover and surface reflectivity, making the ice melt faster. Loss of sea ice also weakens the natural buffers that dampen ocean waves and help prevent the ends of glaciers snapping off and becoming icebergs. It also means less habitat for algae and krill, and reduces breeding platforms for penguins and seals.

Ecosystems under stress

A rainier climate will have a series of ecological impacts.

Water can flood penguin nest sites. Penguins evolved in a polar desert and aren’t adapted for rain. Their chicks’ fluffy feathers are not waterproof, so heavy rain drenches them, sometimes leading to hypothermia and death.

Together with a warming ocean, decreased sea ice and decreased krill, this pressure will affect penguins across the continent. Iconic Antarctic species such as ice-dependent Adélie and chinstrap penguins are at risk of being replaced as more adaptable gentoo penguins expand southwards.

Rainfall also alters life on smaller scales. When it strips away snow cover, it disrupts snow algae – microscopic plants that contribute to Antarctic land ecosystems. These algae feed microbes and tiny invertebrates and can darken the snow surface, increasing solar absorption and accelerating melt.

Snow normally insulates the ground, buffering temperature swings and protecting the organisms underneath. Exposed surfaces face harsher, more variable conditions.

At the same time, warming seas may make it easier for invasive marine species such as certain mussels or crabs to colonise the area.

Challenges for scientists

Humans are also not immune to the challenges posed by a rainier Antarctic Peninsula.

With increasing geopolitical interest, it is likely that human infrastructure will increase, with potential new settlements and bases to serve emerging industries such as tourism or krill fishing.

Research infrastructure was designed for snow, not sustained rainfall. Rain freezing on airstrips renders them unusable until the ice is melted. Slush and meltwater can damage buildings, tents, instruments and vehicles. Clothing and equipment may need to be redesigned.

Some entire research sites may have to move. On nearby Alexander Island, increased surface melt has already disrupted access to long-running ecological research at Mars Oasis – continuously studied since the late 1990s – resulting in gaps in the scientific record.

Heritage at risk

Historic sites are especially vulnerable.

Antarctica contains 92 designated historic sites and monuments, the result of two centuries of exploration and research. Many of these timber huts, equipment stores and early scientific installations are clustered on the peninsula.

In a warmer and wetter climate, thawing permafrost and heavier rainfall threaten the structural integrity of these sites. Timber will deteriorate faster. Foundations will sink. These sites will need more frequent maintenance, in a part of the world where conservation work is already logistically difficult.

The Antarctic Peninsula is already undergoing rapid change. If global warming moves towards 2°C or 3°C this century, extreme weather, rainfall and surface melt will intensify. Damage to ecosystems, infrastructure, glaciers and heritage sites could be severe and potentially irreversible.

Rain, once a rarity in Antarctica, is becoming a force capable of reshaping life on the peninsula. Limiting warming to below 1.5°C won’t prevent these changes entirely. But it could slow how quickly rainfall transforms the frozen continent.

Bethan Davies receives funding from the FCDO Polar Regions Department.

– ref. Rain is coming to Antarctica – here’s what will change – https://theconversation.com/rain-is-coming-to-antarctica-heres-what-will-change-276140

Source: The Conversation – UK – By Michel Dugon, Head of the Venom System Lab, University of Galway

For people living in temperate regions of Europe, the Americas and much of Asia, scorpion stings are rarely a concern. But for millions of children growing up across the subtropical belt, a scorpion sting can have devastating consequences.

While snakebites are receiving increasing international attention and funding under the leadership of the World Health Organization, scorpionism (the medical term for illness caused by scorpion venom) remains under-reported, under-funded and under-researched. Worse still, this silent epidemic appears to be growing, fuelled by a combination of climate change, urbanisation, global trade and human encroachment into natural habitats.

In Brazil, scorpion stings have tripled over the past decade, as scorpions settle in major cities around the country. In Sudan, the construction of the Merowe Dam in 2009 and the rapid development of gold mining complexes displaced scorpion populations into nearby settlements, triggering localised epidemics.

In November 2021, torrential rains in Aswan, southern Egypt, drove thousands of deathstalker scorpions into homes and in the streets, injuring more than 450 residents and overwhelming local hospitals.

Globally, at least 1.2 million scorpion stings are recorded each year. While most victims recover fully, an estimated 3,000 people die annually as a direct result of scorpion stings, mostly children under the age of 13, typically from poor rural communities.

Global hotspots for scorpion deaths:

Scorpionism is not evenly distributed across the tropics. Most fatal cases occur in a dozen geographic hotspots including parts of Latin America, north Africa, the Levant, Iran and western India. All these areas have warm climates with seasonal extremes that favour scorpion activity, as well as poor housing, rapid urbanisation and limited access to healthcare that also contribute to the problem.

Scorpions thrive where people live and work – in cracks in walls, beneath rubble, among stored goods, in outdoor latrines and across agricultural land. But they are not aggressive animals. Most stings occur defensively when a scorpion is accidentally trapped or pressed against the skin.

Lethal scorpions

Of the roughly 2,500 known scorpion species worldwide, only 50 to 100 are considered lethal to humans. Severe envenoming – cases that requiring extensive medical attention and a hospital stay – usually involves intense local pain rapidly followed by profuse sweating, excessive salivation, vomiting and irregular heartbeat. In severe cases, fluid accumulates in the lungs, leading to respiratory failure.

Intensive care beds, ventilation support and medications that stabilise heart and lung function are essential to help young patients withstand the first 24 to 36 hours following severe envenoming.

Antivenom serum developed over a century ago has significantly helped to reduce death rates in parts of Mexico, South America and Egypt. But it is not a magic bullet.

The antivenom must be administered early, requires trained personnel and appropriate facilities, and is only effective if it matches the venom of the species responsible for the sting. It can also cause severe allergic reactions including anaphylaxis. For many vulnerable communities, its cost and limited availability remain major barriers to effective treatment.

Morocco’s scorpion hotspots

Morocco illustrates the complexity of managing scorpion stings. The country hosts more than 55 scorpion species including some of the most dangerous in the world, such as members of the genus Androctonus (“man-killer” in Greek).

After years of limited success with antivenom therapy, in the early 2000s Moroccan health authorities shifted away from antivenom to focus on using respirators and other drugs to control patients’ heart rates and maintain vital organ function while in intensive care. They also began large-scale public education campaigns.

This led to a significant drop in the death rate due to scorpion stings.

Today, Morocco records around 25,000 stings annually, resulting in 50 to 100 deaths. But some areas are much more at risk than others. The rural district of Kalaat Sraghna on the northern slopes of the Atlas Mountains, for example, represents less than 2% of Morocco’s population but accounts for roughly 20% of stings nationwide. Geographic isolation, scorpion diversity and urban expansion are all likely to be contributing factors.

In most cases, the species responsible for a sting is never identified, yet this information can be critical for diagnosis and treatment. Scorpions often look similar and typically escape immediately after stinging. Neither victims nor healthcare workers can reasonably be expected to identify them accurately.

This is where zoology and ecology intersect with public health. In a new study, our team comprising Moroccan and Irish researchers conducted field surveys of 19 scorpion species and then used machine learning (a type of artificial intelligence) to understand where else they might be located throughout Morocco.

Our model identifies the environmental conditions scorpion hotspots might share, including average or extreme seasonal temperatures, annual rainfall, vegetation type and land use. It then scans the landscape for areas with similar conditions, generating probability maps of where each species is most likely to occur.

In our study, we found that soil type was the most important variable driving the distribution of high-risk scorpions across central Morocco.

We recently presented our results at the Pasteur Institute of Morocco in Casablanca, part of the country’s public health system. Our predictive maps can help prioritise intensive care capacity, ensure medications are available locally, and strengthen emergency response in rural areas by helping doctors anticipate which species have been responsible for the stings.

Importantly, this approach can be adapted to other countries facing similar challenges. Scorpionism is still overlooked on the global health agenda. But better integration of ecology, climate science and clinical sciences offers a powerful tool to prevent deaths, especially among vulnerable children.

Michel Dugon receives funding from the EU Erasmus Plus programme for staff and student mobility between the University Ibn Zohr of Agadir (Morocco) and the University of Galway (Ireland)

– ref. Scorpions can pose a deadly threat to children – we’re identifying the global hotspots – https://theconversation.com/scorpions-can-pose-a-deadly-threat-to-children-were-identifying-the-global-hotspots-276340

Source: The Conversation – UK – By John Noone, Assistant Professor & Course Director BSc Sport and Exercise Sciences, University of Limerick

During hibernation, brown bears spend up to six months lying almost completely still, without eating, drinking or exercising. When spring arrives, they leave their dens with their muscles largely intact.

For humans, the same period of inactivity would usually mean severe muscle loss, weakness and long-term health problems. Even a few weeks in bed after surgery can reduce strength and mobility. For older adults, hospital patients and people with chronic illness, long-term immobility can permanently change quality of life. How do bears manage what humans cannot?

To explore this question, my colleagues and I studied how bears protect their muscles during hibernation. Our findings, published in Acta Physiologica, suggest that the answer lies deep inside their muscle cells, in the way they manage energy over long periods of inactivity.

Muscle cells rely on structures called mitochondria to supply the energy needed for movement and basic function. These structures convert nutrients into fuel, allowing muscles to contract, repair themselves and adapt to stress. In people who stop moving for long periods, mitochondria usually decline in both number and performance. Energy production drops. Muscles weaken. Recovery becomes harder.

Bears take a different approach. During hibernation, their muscles contain fewer mitochondria, but the ones that remain work more efficiently. Rather than allowing their energy systems to deteriorate, bears streamline them. They reduce what is unnecessary and preserve what is essential. It is similar to shutting down some power stations during low demand, while upgrading the remaining ones to run more smoothly.

Inside mitochondria, energy is generated through a series of linked chemical reactions. These reactions normally rely on several entry points and fuel sources. During hibernation, bears reorganise this system.

Our research shows that they shift towards alternative energy pathways that function well at low body temperatures. Some parts of the usual machinery are reduced, while others become more important.

At the same time, bears maintain the ability to use both fat and carbohydrates. Fat provides most of the energy during winter, but flexibility remains essential. If conditions change, their muscles can adapt quickly. This reorganisation allows bears to produce enough energy to preserve muscle tissue, even while their overall metabolism slows dramatically.

Temperature plays a central role. As bears cool during hibernation, chemical reactions slow. Instead of fighting this, their muscles adjust. The structure and function of mitochondria change in ways that suit colder conditions.

This temperature-driven control acts like a natural protective system. It limits damage, reduces waste and helps prevent the breakdown that usually follows long periods of inactivity.

To understand these changes, we studied wild brown bears in Sweden during both winter and summer.

In winter, locating hibernating bears meant tracking them to hidden dens beneath deep snow. Teams worked with wildlife experts and veterinarians to safely monitor the animals and collect small muscle samples.

In summer, the challenge was different. Active bears roam huge areas and are difficult to approach. Helicopters were used to locate them, and professionals carefully sedated the animals so that biopsies could be taken safely.

Once collected, the samples were swiftly analysed. The main technique we used measures how well mitochondria produce energy in real time and only works on fresh tissue.

Comparing winter and summer samples revealed a consistent pattern. Bears reduce the number of mitochondria during hibernation but preserve their function. Energy pathways are reorganised, fuel use remains flexible and cellular damage is limited. Together, these changes allow bears to remain strong despite months of immobility.

Connecting wildlife biology with human health

The findings help explain one of nature’s most impressive examples of physical resilience. But their importance goes far beyond wildlife biology.

In humans, muscle loss is a major problem in ageing, long hospital stays, injury recovery and chronic disease. Once muscle is lost, it is difficult to rebuild. Weakness increases the risk of falls, disability and loss of independence.

Treatments rely mainly on exercise and nutrition, which are often hard to apply when people are very ill or immobile. Bears show that another approach is possible.

By making mitochondria more efficient, reorganising energy systems, and responding to temperature, their muscles remain protected even in extreme conditions. Understanding how this happens could guide future treatments that help preserve muscle in vulnerable people.

This research also has relevance beyond medicine. Astronauts lose muscle rapidly in space, and long space missions require better ways to protect physical health in low-gravity environments.

From frozen dens in Scandinavian forests to high-tech laboratories, this work connects wildlife biology with human health and space science.

Bears do not simply sleep through winter. Their muscles follow a carefully controlled programme of energy management, conservation and protection. In doing so, they leave a clear pawprint for human biology: resilience is not about maintaining everything, but about protecting the systems that matter most.

The long-term funding of Scandinavian Brown Bear Research Project (SBBRP) has come primarily from the Swedish Environmental Protection Agency and the Norwegian Environment Agency. This research was funded by the French National Space Agency (CNES, BEAR2MAN project), the French National Research Agency (ANR; B-STRONG project), the University of Strasbourg (H2E project) and the French National Center for Scientific Research (CNRS) MITI.

– ref. Hibernating bears reveal clues to fighting muscle loss – new study – https://theconversation.com/hibernating-bears-reveal-clues-to-fighting-muscle-loss-new-study-275984