Why do Huskies have blue eyes?

Humans have been exercising selection in dogs since the domestication of the wolf. In the first instance we found a natural and quite gradual selection in the way in which the first dogs were domesticated; in second, an intense artificial selection during the formation of the most modern races.

An unintended consequence of this selection is that the canine genome now encodes a phenotypic diversity - characteristics that a gene, eg, blue eyes or brown eyes - can express dramatically high. This variety is susceptible to genetic analysis, and this is demonstrated by the latest study published recently in the journal PLOS Genetics by Adam Boyko and Aaron Sams, of the company Embark Veterinary Inc, and conducted in collaboration with the University of Veterinary Medicine of Cornell.

According to the authors, this represents the first consumer genomics study conducted in a non-human model and the largest study of the canine genome to date. It addresses the reason why huskies have blue eyes. In dogs, the blue eyes are iconic of the Siberian husky, a race of northern latitudes and although it is known that two genetic variants underlie the color of blue eyes in some dogs, these do not serve to explain the trait of the huskies.

To find out this last reason, Boyko and Sams who in his company had the sequenced genome of 6,070 dogs, made use of the information provided by the owners of the dogs and who, through online surveys and photographs, provided the scientists with data on the phenotype studied, in this case the eye color.

Thus, scientists discovered that chromosome 18 near the ALX4 gene, which plays an important role in mammalian eye development, was strongly associated with the variation in blue color for the eyes, mainly in Siberian huskies, but also in the Australian shepherds that do not show the merle mutation (which dilutes the color of melanin in dogs and mice). Thus, only one copy of the variant is sufficient to cause blue eyes or heterochromia - blue and brown eyes - in many of the individuals studied.

However, some dogs with the variant did not have blue eyes, so the researchers hypothesize that other genetic or environmental factors could be involved in the expression of this phenotype. Future studies on this mechanism may lead to the discovery of a new way in which blue eyes develop in mammals.

On the other hand, from a broader perspective, the results emphasize the power of knowledge based on the data provided by consumers. In words that Aaron J. Sams sends us via press release: "by using the genetic data of our clients' pets, combined with the colors of the eyes reported by them, we have discovered a genetic duplication that is strongly associated with the color of blue eyes In a single year, we gathered enough data to make the largest canine study of its kind, "he adds. "In addition, we are currently conducting similar research projects with respect to morphological or health-related characteristics, which benefit reproduction efforts and the welfare of dogs in the first place, but are valuable in the same way for studies. in humans, since dogs and humans exhibit many physical features, behaviors and analogous diseases in a shared environment, with this new methodology we hope to achieve great advances in the field of genetics and medicine ", concludes the researcher.

Rainforest animals

What animals live in the rainforest?

The tropical forests have an enormous biodiversity. It is estimated that up to half of the species that inhabit the planet, are living in this ecosystem. We can find jungles of this type in the vicinity of Ecuador, South America, Africa, some Southeast Asian Islands, Mexico, Central America, Madagascar, Indochina or Northwest Australia and in them we can find fascinating and very varied animals. In this article we talk about which animals live in the rainforest.

What conditions do tropical forests have?

The conditions that occur in the rainforests are characteristic of the low latitudes in which they are found, with an average temperature of around 25ºC to 30ºC throughout the year and rainfall that can occur throughout the year, including daily , it is common to reach a minimum volume of 100 mm up to about 400 inches of rainfall per year, although this is quite variable. What is common is that these forests reach a very high humidity, from 75 to 90%. These forests, unlike others, do not change their conditions much over a year, but are more or less stable. Given this great humidity and heat, large clusters of clouds are created over these forests.

Due to this high degree of humidity, they are also very dense in terms of vegetation, being common a broadleaf vegetation: trees, shrubs, ferns, etc. That prevent sunlight from reaching the ground, so it also favors the development of mosses and fungi.

Strata of the rainforest

These forests are usually divided into 4 zones or strata (from top to bottom) and they inhabit different animals, because in each stratum there are somewhat different conditions.

• Emerging stratum: it is the area determined by the tallest trees, which are usually hardwood and broadleaf, reaching up to 60 meters in height. In this area, the strong wind blows and pulls the seeds, which are deposited in the surrounding land for the new generation. It is an area inhabited by bats, butterflies, monkeys and birds.
• Stratum of the canopy: it is considered the primary layer of the forest. It is formed by a labyrinth of branches and leaves that protect the lower strata of sunlight and rain. In this area food abounds and you can find butterflies, frogs, toucans and snakes.
• Underbrush layer: also protects the lower layer of sunlight. In this stratum, shrubs of up to 4 meters live and most insects, tree frogs, snakes, jaguars and leopards inhabit it.
• Stratum of the soil: it is a very dark zone, where vegetation hardly develops. This land cover, buds, branches and twigs. In this area, so-called soil recyclers live, such as giant anteaters, cockroaches and large millipedes. It is called recyclers because they are animals that feed and decompose leaves or plants.

Main animals that live in the tropical jungle

In these forests live so many animals that have not yet documented all the species that inhabit them. Some examples of animals that live in the jungle, both carnivores and herbivores, are:

• Jaguars: are common in the jungles of America, is the largest predator of the jungle with other cats and crocodiles. It is a feline with golden and yellow fur with some small reddish to black spots. They can reach 130 kg in weight and 2.30 meters. It is an opportunistic carnivore that feeds on mammals, reptiles, insects, fish and invertebrates.
• Pumas: feline up to two meters and 72 kg in weight. It feeds on insects and large ungulates.
• Ocelot: feline of fur with spots and average size that measures up to 90 centimeters and weighs 11 kg. It feeds on rodents, monkeys or reptiles. It is one of the animals in danger of extinction in Mexico.
• Tiger: the largest feline there is. The tiger is a very fast animal that can reach 300 kg of weight and 380 centimeters.
• Crocodile of the Nile: it is a reptile that lives in jungles of Africa. It feeds on mammals, fish or other reptiles. Above all, he captures them when they come to drink.
• Elephant: are relatively medium elephants for their species, up to two and a half meters. There is an African elephant and Asian elephants, like the elephant of Sumatra, who live in the jungle. The rest of the elephants that are larger live in areas like the African savanna and not in jungles.
• Capybaras: are the largest rodents. They live in herds and are of twilight activity
• Cockatoos: there are up to 21 species of cockatoos in the jungle. They are very showy birds.

Other animals in the rainforest are leopards, panthers, lemurs, anteaters, rock pythons, mambas, tapirs, eagles, macaws and numerous species of parrots, ostriches, chimpanzees and other monkeys.

Wild animals also age

Until a few years ago, the scientific community defended the belief that wild animals died before getting old, mainly by the action of predators or by the presence of parasites. However, the elements opposed to them in a habitat or hostile ecosystem do not manage to get ahead completely over time. It was not until 2011 that aging and senescence in nature were first demonstrated.

The first animals that were monitored to determine their pattern of aging were the blue-footed boobies (Sula nebouxii).

These birds are especially long-lived and inhabit the Pacific coast between Mexico, the Galapagos Islands and Peru. The results obtained show that the germ line, the DNA that gives continuity to the following generations, can be damaged with age. Just as the offspring of men whose age exceeds 50 years is more at risk of genetic diseases, the same happens with these birds. The DNA of older birds is damaged and can make their offspring more prone to diseases or mutations.

For the blue-footed boobies, it is precisely the color of their limbs that makes the difference. The coloring of the legs suffers aging and is an indicator of oxidative damage in sperm, so older males tend to have more muted colors, while middle-aged males have a less damaged germ line and more colorful legs. According to the study, females choose males based on the color of the legs and feel less attraction for older subjects, with legs of more subdued colors.

Before this study, the general belief was that senescence, the natural problems or deteriorations of the body associated with the passage of time and age, only manifested in humans and domestic animals because we have a life expectancy much higher than that would correspond to us in a natural way; We live longer than we would touch. However, the discoveries made by Alberto Velando as the main leader of the research show that senescence exists in nature and that it affects the ability to live and reproduce of wild animals.

The results of the research allowed to open a new field of perspectives on what is behind the sexual signals and served as a first indication of the importance of sexual selection to purge genetic mutations.

Marine life also counts

For the first time in history, experts from around the world have met to talk at length about the life of the oceans at the First World Congress on Marine Biodiversity, held in Valencia, Spain. It has presented the progress of the project that, in the year 2000, brought together thousands of scientists from 82 countries with a common goal: to explore the biodiversity of the oceans. Although the catalog of species will not be completed until 2010, the Marine Life Census (CoML), as this network is known, has already provided some interesting data. For example, researchers have found evidence that first evidence that a large proportion of octopus species from around the world evolved from a common ancestor that still lives in the Antarctic. In this same ocean, giant starfish have been identified. And the Pacific has surprised us with a white shark coffee? and a "sturgeon park".

Biologists do not want to leave anything behind. For they are exploring from the intertidal zones shared with humans to the dark trenches of more than 10,000 meters deep, from the microscopic plankton of the illuminated areas of the sea and the sea lions that dive in the depths to the worms that inhabit the abysmal sediments , from the organisms that live in the changing slopes of the seamounts to those that tolerate fiery oceanic sewers. In other words, 5% of the oceans that are regularly visited and 95% whose life remains unexplored.

Normal bees and killer bees

Africanized bees, commonly known as "killer bees", are much more aggressive than their European counterparts. Now, a team of researchers have examined the changes in neuropeptides that take place in the brains of these bees during their aggressive behavior and have shown that they can turn normal bees into 'killer' by injecting certain peptides.

Only a few neuropeptides make the difference between a honey bee and another that has an irritable need to wipe out everything that moves.

To discover what it is that makes Africanized "killer bees" so hostile, the State scientists at the University of São Paulo (Brazil) compared their neurochemistry with that of their more docile relatives and found that it is mostly due to a surprisingly simple chemical change.

The reputation of killer bees is well deserved. Its venom is no more lethal than average honey bees and they are even a little smaller, but they are incredibly aggressive, and it does not take much provocation to incite a swarm of these bees to become a furious and poignant pain machine.

The more hostile an animal is, the more caution you have to have

These bad-tempered striped insects appeared in the late 1950s, after Brazilian beekeepers imported an African variety of Apis mellifera scutellata in order to increase honey production. It seems that the bees did not understand the fine print very well and ended up paying for the honey bees.

Since then, these aggressive hybrids have spread to northern California and remain a legitimate threat. Several hundred people have lost their lives due to their implacable twinge. And is that this subspecies is also extremely sensitive to the presence of humans. They usually attack the eyes and the face, and the only thing that can be done before them is to run away.

But what happens in your brain to act in this way?

To get to the bottom of the mystery, the researchers of this last study had to collect a sample of killer bees (something not without danger). Using a rather curious trick they managed to catch them to observe their tiny brains.

The comparison of the full range of brain proteins from two bee samples using mass spectral imaging revealed a clear, but simple difference.

One of the suspected proteins was called Apis mellifera Allatostatins A, a neuroprotein that is already known to play a key role in the learning and memory of bees, as well as in their overall development.

The other group of proteins, described as tachykinin-related peptides, seems to influence sensory processing.

In aggressive hybrids, these two groups of neuropeptides had been cut into shorter proteins, and found in different groups of brain tissue called neuropiles.

To verify that these proteins were significant in the transformation of the behavior of the bee, the scientists injected in the brain of a group of non-aggressive bees truncated forms of these neuropeptides.

As expected, the bees did not seem very happy when they woke up, because having modified their brain chemistry they had also become killer bees.

However, it is still unknown why the size and distribution of these neuropeptides lead to such aggressive behavior. Learning more about the cascade of effects that these proteins have on the nervous system of a bee could tell us more about the development of the nervous systems of bees, as well as those of insects in general.

Curiosities about polar bears

The lion is par excellence the king of the jungle, but if we change the scenery and drastically lower temperatures, the polar bear becomes, without any doubt, the new and legitimate monarch.

These amazing creatures inhabit the waters covered by the Arctic ice, extending from Canada, Norway or Denmark, to some areas of Russia and even, to a lesser extent, in Iceland. This causes that the idea that the polar bears unfold with great ease in adverse conditions and extremely dangerous for any other type of living being is reaffirmed.

It is estimated that there are currently between 22,000 and 32,000 copies worldwide, indices that, due to their progressive decline, have awakened for years the concern of biologists and scientists. In fact, this species has become the reference for the health status of ecosystems. Unfortunately, the extreme situation of polar bears is a powerful indicator of the lack of effective environmental policies worldwide.

For more than twenty years, polar bears have been forced (and increasingly) to travel long distances during the summer periods in search of frozen areas. Precisely, it is the ice that depends on obtaining food from these animals, because it is what allows them to hunt. The rise of temperatures delays the solidification of the water and therefore, delay (and shorten) the feeding period of the bears. Unfortunately, it is increasingly common to find these animals in a serious state of malnutrition. The most prone to this are the females with puppies that inhabit the areas further south of their range.

Organizations such as the Oceanic Administration of the USA have carried out different research on the environmental impact of the melting of the Arctic plates. The latest results have been alarming, since 2016 recorded the smallest sea ice surface in the last 37 years.

Despite the difficulties, the polar bear is still one of the most impressive creatures on the planet, as its characteristics make it an icon of the animal kingdom. In the next gallery we show you everything you need to know about this vulnerable, but powerful species.

Evolution

The polar bear (Ursus maritimus) evolved from a population of brown bears during the Pleistocene. Some research suggests that this process began about 38 million years ago, when a large group of bears separated and adapted to new living conditions.

800 kilos

It is the largest terrestrial animal. It measures up to 3 meters from the snout at the end of the tail, and weighs up to 800 kilograms (the male). However, they have relatively small heads.

Family of 3

The polar bears have two young per litter after a gestation period of 6.5 to 9 months. The young remain with the mother for 2 or 3 years. The rest of the time, they are solitary animals.

Tireless travelers

The polar bear can travel up to 1000 kilometers in the changing seasons, when the ice melts or freezes, either walking on the ice or swimming. His nose is so sharp that he can smell a seal 32 kilometers away.

Black under a white coat

Under the white fur, the polar bear's skin is black, which helps him absorb the sun's rays. In addition, it has a thick layer of grease to withstand polar temperatures. Its double fur coat repels water and, thanks to its white color, helps it to camouflage itself.

At 37 degrees

The polar bears, in addition, maintain an average temperature of 37 degrees. The reason why they endure extreme temperatures is that in addition to their thick and hard skin layer, these animals have a thick layer of extra fat. This is the cause of its thermoregulation. However, that same layer is what causes them to have a rapid overheating and can not withstand high temperatures.

Lazy

Polar bears are inactive most of the time (66.6% of their lives). Overheating is one of the main factors by which this species moves at a low speed and usually lie down to rest.

Playing live more

The polar bears that play live longer, enjoy better health and have more offspring, according to a recent study by the ethologist Robert Fagan of the University of Alaska.

A great smell

One of the most developed senses of the polar bear is its smell. It is so sharp that you can smell the seal of a seal more than 30 kilometers away, something very useful considering the difficulties to find food. In addition, it is very important to identify any type of danger that may lurk around you.

Feeding

They can eat up to 30 kilos of food in the same day. Its main source of food are seals. They have 42 sharp teeth, which allow them to easily devour their prey. These pieces are longer than those that the brown bear has in its mouth.

They dive

Sometimes, when stalking their prey, the polar bears are submerged in the water thanks to the adaptations of their legs. This activity is also performed to find algae, cleanse or reduce body temperature. It is estimated that they can remain submerged for 2 minutes at depths between 3 and 5 meters.

Always clean

This species is extremely clean, because after hunting and devour their prey, always spend time to remove with water and snow the remains of the animal in your body. Researchers suggest that, because they are so sensitive to smell, they are uncomfortable with the smell and need to remove it immediately.

Satellite tracking

WWF and Canon have developed the online tool (Polar Bear Tracker) that allows us to follow their migratory movements in the archipelago of Svalbard, Norway, the Sea of ​​Beaufort, Alaska, the Bay of Hudson and Canada. The use of collars with satellite devices helps to closely monitor their movements, expand knowledge of their habits and know how they are affecting the impacts of climate change.

In danger

The polar bear is listed as a vulnerable species in the Red List of Endangered Species of the International Union for Conservation of Nature. According to reports from the World Wildlife Fund, these creatures could disappear during the next century if the destruction of their ecosystem is not stopped.

Giraffes surprise scientists again

So far, the theory that the size of groups of wild animals is larger when the risk of them being attacked by their direct enemies, the predators, is generally accepted. This is basically due to the fact that the more members that make up the collective, the more protected they will be and the more easily they will be able to detect and warn of a danger. However, a new study (the first to investigate this group tendency) of the University of Bristol (England) has shown that this assumption was not entirely true, or at least not in the case of giraffes.

This study has been based on observing how the grouping of these animals differs from the rest in factors such as the risk of predation, the type of habitat and the characteristics of the individuals that haunt. The type of habitat had remarkable effects on the size of the group. However, the main change was reflected in the behavior of adult females, who tended to be in smaller groups when they were in procreation and had offspring. This last data belies another popular belief that giraffes were thought to form large groups for the community care of their offspring.

The researcher and doctoral student Zoe Muller says that "these data are surprising and reflect how little we know about giraffes, even in the most basic aspects of life. This research adds another important piece to the puzzle of understanding how giraffes live in nature. "

Extraordinary animals in danger of extinction

It is estimated that giraffe populations have decreased by approximately 40% in the last three decades. Among the survivors, it is thought that there are just under 98,000 individuals left in freedom. These figures have led to the inclusion of the species in the Red List of Endangered Species of the International Union for Conservation in Nature and has been classified as 'vulnerable'. Experts see this as a valuable step in recognizing the seriousness of their extinction, and understanding the threats and challenges they face in nature.

"Giraffes are an endangered species that suffer a constant decline in Africa, and this research highlights how incredibly misunderstood they are, and we can only manage and conserve giraffe populations effectively if we understand their behavior and ecology, which is what we are just beginning to do, "says Muller.

Another of the popular ideas of the society is that giraffes abound in Africa and for that reason, they point to it as an indisputable icon of the continent. However, the figures reveal a very different reality, since its decline is progressive and accelerated.

The next step in this investigation is to expand the project to different areas of Africa, since this study has been carried out only in the eastern part. According to Muller, more research is needed to see if the same effects are observed in other groups of giraffes. The extracted results could be used to understand how the habitat alteration and other environmental and social variables can help the conservation of the populations of this species.

Good news for mountain gorillas

If Dian Fossey, the popular zoologist author of the book "Gorillas in the Mist" was alive, surely today would have many reasons to be happy. And, according to the data of the last census, the population of mountain gorillas (Gorilla beringei beringei) has doubled in the last three decades.

"This is one of those very rare conservation news," explains Martha Robbins, an expert gorilla researcher at the Max Planck Institute for Evolutionary Anthropology. "Despite the poaching, the degradation of their habitat and the civil war, the population of gorillas in the Virunga mountains has doubled."

To estimate the number of individuals of this endangered species, a field campaign was conducted between 2015 and 2016. The teams kicked more than 2,000 kilometers through the Virunga Mountains looking for tracks and other signs of the presence of gorillas. In addition, genetic analyzes were made that took more than 18 months to complete and studied more than a thousand fecal samples, determining that there are at least 186 gorillas not used to human contact. The researchers estimate that the current total population of mountain gorillas in the Virunga volcanoes surpasses the six hundred specimens that would be distributed in 41 social groups, and 14 of them would be solitary males. To this figure we must add the approximately 400 individuals that live in the Impenetrable National Park of Bwindi, in Uganda, for which we speak of a total of more than 1,000 gorillas.

More accurate census methods

The last census had been made in 2010 and estimated a population of 480 gorillas. The current figure represents an increase of 26% in a period of only six years, which means an annual growth rate of 3.8%. Although it is true that the study methods are now much more precise, so it is possible that in previous censuses had estimated "down", the truth is that there has been real growth in the population, as reported by the Max Institute Planck.

"The genetic analysis of fecal samples allows us to count gorillas without having to observe them," explains Linda Vigilant, director of the genetics laboratory specializing in primatology in Leipzig. "It will also allow us to obtain more information about how social groups are formed and the changes that occur in them over time."

"This result is the result of the efforts made by the governments of Rwanda, Uganda and the Democratic Republic of the Congo to keep the great apes in danger of extinction and, in particular, the hard work of the staff working in the field," says Robbins . "The spectacular increase in the population of gorillas shows that the efforts made in terms of sustainable tourism, veterinary work and community projects can have a positive impact on one of our closest living relatives."

Much remains to be done in the Virunga mountains, for example, to improve the security of forest agents and tourists. Only in the last ten months have twelve workers been killed in the park, and in the last incident two British tourists were abducted. Due to this, the Virunga National Park is currently closed to the public to improve its security protocols and, according to The Guardian, will not open its doors until next year.

DNA from ancient animals will help trace cultural exchanges in China

Chinese archaeologists plan to use DNA from ancient domestic animals to establish their importance in cultural exchanges along the Silk Road in China.

Experts from Jilin University, located in the city of Changchun, capital of Jilin Province, northeast China, will collect samples of remains of domestic animals that have been discovered at various sites along the Silk Road. , to perform analysis of the entire genome.

Domesticated animals contributed to trade and trade as a stable resource of protein and energy.

Cai Dawei, a professor at the university, said the research would be a new vision of the development of the Silk Road.

The trip of an imperial emissary named Zhang Qian to the western regions around the year 140 a. C. is generally considered to be the beginning of cultural exchanges between East and West, but recent archaeological finds show that such activities actually began in prehistoric times. According to Cai, at the end of the Paleolithic they would already be taking place.

Among the first examples of exchanges are the arrival in the East of bronze smelting and domesticated animals, such as horses and cattle, and the introduction in the West of millet and decorated pottery.

The researchers, who have the support of China's National Social Science Fund and the cooperation of archaeologists from Central Asia and Europe, hope to complete their studies in 2022.

Brazilian researchers discover 12 new species of animals in the Amazon

Brazilian researchers discovered 12 new species of animals in the Amazon, the largest forest in the world, in two expeditions that were used to analyze more than 1,700 specimens of more than 200 species of animals and plants.

According to state agency Agencia Brasil, the 12 new species are toads and lizards, as well as an owl.

All of them were identified in two expeditions, one carried out at the end of last year and the other between April and May of this year, financed by the Research Support Foundation of the State of Sao Paulo (Fapesp, for its acronym in Portuguese).

As explained by the zoologist of the University of Sao Paulo (USP) and leader of the expeditions, Miguel Trefaut Rodrigues, the objective was "to study the influence of the waters of the Rio Branco on the diversity and abundance of species".

The Rio Branco is an Amazonian river in Brazil and the main tributary of the northern margin of the Río Negro, which runs entirely through the northern state of Roraima, bordering Venezuela and Guyana.

The expedition also collected data to study the influence of the Río Negro as a barrier to the transit of species.

"For this reason we collected on both sides," added Trefaut Rodrigues, who said that the Rio Negro (the largest of all tributaries of the Amazon River and the largest blackwater in the world) does not have many species of animals to have very acidic.

The expedition also aimed to understand the origin of lizards of the genus Loxopholis that reproduce asexually and that has several species formed only by females.

The material obtained will be used to analyze the evolutionary patterns of the fauna of South America.

"Several groups of animals are being studied from a genetic, morphological and physiological point of view, and some of these studies will help understand the extinction risk of these species if the temperature rises in the next few years," he said.

Animals are getting more nocturnal to avoid humans

Animals that are millions of years old being diurnal are moving into the night. Whether big or small, forest or savanna, predators or prey, species from all over the planet are transferring the bulk of their activity to the night time. A large study points to the expansive human presence as the cause of changes that can disrupt the dynamics of entire ecosystems.

The impact of humans on wildlife has many edges. The most obvious is the contraction of the space available to animals as the human race has been expanding throughout the planet. In addition, these natural spaces are increasingly reduced and quartered and their quality is reduced with each new infrastructure that surrounds them. One of the consequences of all this is that animals move less and less in areas with human presence and take refuge in increasingly smaller areas. But there is another way to hide from humans: leave when they go to bed.

A group of researchers from the United States has verified the global nature of this translation of animal life to the hours in which the great diurnal predator rests. Compiling the results of dozens of studies on the movements of some 60 species of mammals from five continents, scientists have found that, where there is a human disturbance, mammals are, on average, 1.36 times more nocturnal. This means that an animal that, without disturbances, equally distributes its activities between day and night, would increase its nocturnal activity up to 68%.

"There is evidence to suggest that animals everywhere are adjusting their daily activity patterns to avoid humans over time, as it is increasingly difficult to avoid them in space," says the researcher at the University of California at Berkeley. (USA) and principal author of the study, Kaitlyn Gaynor. "As people are more active by day, animals are moving into the night," he adds. This transfer occurs whether it is herbivores or large carnivores such as the tiger. The pattern is repeated both in smaller mammals such as the opossum, and in those weighing more than 3,500 kilograms, such as the African elephant.

The most striking aspect of this review, published in the journal Science, may be that animals are becoming more nocturnal regardless of the level of danger that humans pose. "We expected to find a tendency to increase nocturnality in the vicinity of humans, but We have been surprised by the consistency of the results. The animals respond to all types of human disturbance, regardless of whether it really poses a direct threat, "he adds.

Gaynor's work is based on dozens of studies that used various tracking techniques (beacons, collars with radio transmitters, GPS, phototraps or direct observation) of the movements of the animals before a range of human presences, from hikers to hunters, going through fields or roads. One of those studies tracked a species as opportunistic as the fox for lands of Castilla-La Mancha in a series of minor environments (Cabañeros national park) to greater human presence (around Ciudad Real).

"Although it is a twilight animal, the more human disturbance, the fox tended to reduce its diurnal activity," says the biologist at the University of Malaga and co-author of that study, Francisco Díaz. For the most nocturnal foxes, there was a temporary mismatch with their main prey, the rabbit, eminently diurnal. Fortunately for them, the foxes are among the most adaptive animals. "But there are other species with millions of years of adaptation to daytime behavior that are not so plastic," Díaz recalls.

The consequences of this transfer to the night of so many species are still uncertain. In principle, it would seem that the abandonment of the day in favor of humans would facilitate the coexistence between humans and animals. But such a widespread and rapid change of patterns of activity molded over millennia can alter an entire ecosystem. "In the case of predators not adapted to hunting at night, there could be an increase in the population of the ungulates that were their prey, which would affect the availability of vegetation cover, producing a cascading effect," says the Researcher at Radboud University, Niimega (The Netherlands), Ana Benítez.

For the Spanish ecologist, who has also investigated the different human impacts on animal life, the most relevant of this research is that it confirms a hypothesis raised in the 60s by the biologist Fritz R. Walther: "Animals respond equally to humans , they always see us as predators, "he says. This leads to the question whether the impact of a hunter can be the same as that of a nature-loving hiker. For Gaynor, his research "suggests that our mere presence is enough to interfere with natural behavior patterns".