Horses communicate with eyes and mobile ears

Author Jennifer Wathan is shown with study participant Bartie. Credit: Jennifer Wathan

Horses are sensitive to the facial expressions and attention of other horses, including the direction of the eyes and ears. The findings, reported in the Cell Press journal Current Biology on August 4, are a reminder for us humans to look beyond our own limitations and recognize that other species may communicate in ways that we can't, the researchers say. After all, human ears aren't mobile.

"Our study is the first to examine a potential cue to attention that humans do not have: the ears," says Jennifer Wathan of the University of Sussex. "Previous work investigating communication of attention in animals has focused on cues that humans use: body orientation, head orientation, and eye gaze; no one else had gone beyond that. However, we found that in horses their ear position was also a crucial visual signal that other horses respond to. In fact, horses need to see the detailed facial features of both eyes and ears before they use another horse's head direction to guide them."

The new study also challenges the earlier held notion that animals with eyes to the sides of their heads cannot glean information based on the direction of one another's gaze.

Wathan and the study's senior author Karen McComb took photographs to document cues given by horses when they were paying attention to something. Then Wathan and McComb used those photographs as life-sized models for other horses to look at as they chose between two feeding buckets. In each case, the horse in the photo was paying attention to one of the buckets and not the other. In some instances, the researchers also manipulated the image to remove information from key facial areas, including the eyes and the ears.

The researchers' observations show that horses rely on the head orientation of their peers to locate food. However, that ability to read each other's interest level is disrupted when parts of the face -- the eyes and ears -- are covered up with masks. The ability to correctly judge attention also varied depending on the identity of the horse pictured, suggesting that individual facial features may be important, the researchers report.

Wathan and McComb plan to continue to explore facial features related to the expression of emotion in their horses, noting that horses' rich social lives and close relationship to humans make them particularly interesting as study subjects. Our understanding of horses' social lives might also have implications for their welfare.

"Horses display some of the same complex and fluid social organization that we have as humans and that we also see in chimpanzees, elephants, and dolphins," Wathan says. "The challenges that living in these societies create, such as maintaining valuable social relationships on the basis of unpredictable interactions, are thought to have promoted the evolution of advanced social and communicative skills. There is a general interest in studying species with this social structure."

Source: Cell Press

Do women and men ride differently? Horses cannot tell the difference

Horses seem to be truly gender-neutral. It doesn't matter to them if their human partner is female or male.
Credit: Juliane Kuhl / Vetmeduni Vienna

Scientists at the Vetmeduni in Vienna have analysed how horses are affected by the sex of their riders. Various parameters of stress were determined in horses and their riders when they covered an obstacle course. The results were surprising: the level of stress on a horse is independent of whether a man or a woman is in the saddle. Furthermore, the stress responses of male and female riders are essentially the same. The results have been published in the Journal of Comparative Exercise Physiology.

For centuries, horse riding was largely restricted to males. The previous situation is in stark contrast to the present day, when nearly 80 percent of riders are women. Modern-day equestrian sports are unique in that men and women compete directly against one another at all levels, from beginners in gymkhanas to national champions in the Olympic Games. "For this reason it is interesting to consider whether a theory of riding that was developed exclusively for men can be applied to women," explains Natascha Ille, the first author of the recent publication.

A rider is a rider

As Ille notes, "It is often assumed that women are more sensitive towards their horses than men. If this is so, male and female riders should elicit different types of response from their horses." Ille, Christine Aurich and colleagues from the Vetmeduni Vienna´s Graf Lehndorff Institute tested this notion by examining eight horses and sixteen riders, including eight men and eight women. Each horse had to jump a standard course of obstacles twice, ridden once by a male and once by a female of similar equestrian experience. The scientists monitored the levels of stress in the horses and their riders, checking the amounts of cortisol in the saliva and the heart rates.

The results were unexpected. The level of cortisol in horses' saliva increased during the test but the increase was not affected by the sex of the rider. The horses' heart rates also increased as a result of taking the course but the increase was irrespective of the human partner in the saddle. The tests on the riders gave similar conclusions. Again, the level of cortisol in the saliva increased but there was no difference between men and women. The riders' pulses sped up when the horses switched from a walk to a canter and accelerated further during the jumping course. But the heart rate curves for male and female riders were close to identical.

The distribution of saddle pressure is the same for male and female riders
In a second experiment, Ille and her colleagues studied the pressure exerted on a horse's back via the saddle. As she explains, "Depending on the rider's posture and position, the pattern of pressure on the horse's back may change dramatically." A special pad placed directly under the saddle was used to analyse saddle pressure in walk, trot and canter. Because female riders are generally lighter than males, the saddle pressure was lower when horses were ridden by females. However, the distribution of pressure did not differ and there was no evidence of differences in the riding posture between males and females.

A fair chance for all

So what does all this mean for modern equestrian sports? Aurich is keen to reassure potential competitors that horses are truly gender-neutral. As she puts it, "Assuming that there is no difference in riding ability, from the horse's point of view, it does not seem to matter whether the human partner is male or female. Our results make it extremely unlikely that horses have a preference for riders of one sex over the other. And when male and female riders compete against one another in equestrian sports, all of them have similar chances of doing well."

Source: Veterinärmedizinische Universität Wien

Cats and humans have shared the same households for at least 9,000 years, but we still know very little about how our feline friends became domesticated.

The scientists fitted GPS collars and motion sensors on 38 free-ranging lynx for the study. Credit: Image courtesy of Albert-Ludwigs-Universität Freiburg

An international research team recorded and analyzed the activity patterns of 38 wild cats over the course of months Whether a lynx hunts by day or by night and how active it is overall depend primarily on the behavior of the wild cat's most important prey and its individual traits -- lighting conditions, on the other hand, do not play a major role in its basic behavioral patterns. This is the key finding of a study published in the journal PLOS ONE by an international research team led by forest scientist Dr. Marco Heurich.

The scientists fitted GPS collars and motion sensors on 38 free-ranging lynx for the study. Since the study sites were located across a wide latitudinal range from Central Europe to northern Scandinavia, the length of days and nights varied greatly between them. The team recorded and analyzed the activity patterns of the wild cats on a total of more than 11,000 days. The results reveal that lynx in more southerly regions are most active at dawn and dusk and that they move more by night than by day. They take their longest break in the middle of the day, and this break is extended as daylight duration increases. However, the cats exhibit this basic behavioral pattern independently of lighting conditions: "Lynx keep to a 24-hour rhythm with an active and a resting phase even on the polar day and the polar night," reports Heurich.

What the study found to be more important for explaining the wild cats' activity patterns are their individual traits: Young lynx are more active than adult lynx, and male adults are more active than female adults. In addition, they move more in spring and summer than in fall and winter, and the farther north they live, the larger the territory they cover -- and this of course results in higher activity. Lynx adapt their hunting schedule to the behavior of their prey. In polar regions, the height of their activity at dusk is less pronounced. 

This corresponds to the behavioral pattern of reindeer, which exhibit a steady movement profile outside of their sleeping phases.. In Central Europe, by contrast, the team found a maximum amount of activity at dusk -- in lynx as well as in deer. "The findings of this study make an important contribution to our understanding of the habits of predatory animals in our landscape," says Heurich. "They also show that human activities in the areas included in the study do not have a general influence on the activity pattern of the animals."

Cat genome reveals clues to domestication​​

Cats and humans have shared the same households for at least 9,000 years, but we still know very little about how our feline friends became domesticated.

Cats and humans have shared the same households for at least 9,000 years, but we still know very little about how our feline friends became domesticated. An analysis of the cat genome led by researchers at Washington University School of Medicine in St. Louis reveals some surprising clues.

The research appears Nov. 10 in the Proceedings of the National Academy of Sciences Early Edition.

Cats have a relatively recent history of domestication compared with dogs; canines arose from wolves over 30,000 years ago.

"Cats, unlike dogs, are really only semidomesticated," said senior author Wes Warren, PhD, associate professor of genetics at The Genome Institute at Washington University​. "They only recently split off from wild cats, and some even still breed with their wild relatives. So we were surprised to find DNA evidence of their domestication."

One way scientists can understand the genetics of domestication is to look at what parts of the genome are altered in response to living together with humans, Warren added.
The researchers compared the genomes of domestic cats and wild cats, finding specific regions of the domestic cat genome that differed significantly.

The scientists found changes in the domestic cat's genes that other studies have shown are involved in behaviors such as memory, fear and reward-seeking. These types of behaviors -- particularly those when an animal seeks a reward -- generally are thought to be important in the domestication process.

"Humans most likely welcomed cats because they controlled rodents that consumed their grain harvests," said Warren. "We hypothesized that humans would offer cats food as a reward to stick around."

This meant that certain cats that would normally prefer to lead solitary lives in the wild had an additional incentive to stay with humans. Over time, humans preferred to keep cats that were more docile.

Cat genome project

The cat genome sequencing project, funded by the National Human Genome Research Institute, part of the National Institutes of Health (NIH), began in 2007. The project's initial goal was to study hereditary diseases in domestic cats, which are similar in some cases to those that afflict humans, including neurological disorders, and infectious and metabolic diseases.

To obtain the high-quality reference genome needed for this research, the team sequenced a domestic female Abyssinian cat named Cinnamon. They chose this particular cat because they could trace its lineage back several generations. This cat's family also had a particular degenerative eye disorder the researchers wanted to study.

To better understand characteristics of domestication, the researchers sequenced the genomes of select purebred domestic cats. Hallmarks of their domestication include features such as hair color, texture and patterns, as well as facial structure and how docile a cat is. Cats are bred for many of these types of characteristics. In fact, most modern breeds are the result of humans breeding cats for their favorite hair patterns.

The team also looked at a breed called Birman, which has characteristic white paws. The researchers traced the white pattern to just two small changes in a gene associated with hair color. They found that this genetic signature appears in all Birmans, likely showing that humans selectively bred these cats for their white paws and that the change to their genome happened in a remarkably short period of time.

The group also compared the cat genome with those of other mammals -- including a tiger, cow, dog and human -- to understand more about the genetics of cat biology.

"We looked at the underlying genetics to understand why certain abilities to survive in the wild evolved in cats and other carnivores," said Michael Montague, PhD, the study's first author and a postdoctoral research associate at The Genome Institute.

The differences they found in the cat genome help explain characteristics such as why cats are almost exclusively carnivorous and how their vision and sense of smell differ from other animals like dogs.

Solitary carnivores

To digest their fatty, meat-heavy meals, cats need genes to efficiently break down fats. The team found particular fat-metabolizing genes in carnivores such as cats and tigers that changed faster than can be explained by chance. This more rapid change generally means these genes provide some sort of digestive advantage to carnivores that only consume animal proteins. The researchers did not find such changes in the same genes of the cow and human, who eat more varied diets and would not need such enhancements.

Cats also rely less on smell to hunt than dogs. So it is not surprising that the researchers found fewer genes for smell in cats than dogs. But they did find more genes related to an alternate form of smell that detects chemicals called pheromones, which allow cats to monitor their social environment, including seeking out the opposite sex. This ability is not as important to dogs, which tend to travel in packs. But it is crucial in cats, which are more solitary and may have more difficulty finding mates.

Cats also have better hearing than most other carnivores, including an ability to hear in the ultrasonic range to better track prey. Their vision is also exceptional in low light.

"Cats tend to be more active at dawn and dusk," said Montague, "so they need to be able to detect movement in low light." Accordingly, the team identified specific genes that likely evolved to expand cats' hearing range and their vision in low light.

Even though the genomes of domestic cats have changed little since their split from wild cats, the new work shows that it is still possible to see evidence of the species' more recent domestication. "Using advanced genome sequencing technology, we were able to shed light on the genetic signatures of cats' unique biology and survival skills," said Warren. "And we were able to significantly jump start our knowledge about the evolution of cat domestication."

Collaborators in the research include Texas A&M University; University of Missouri-Columbia; University of California-Davis; Wellcome Trust Sanger Institute in the United Kingdom; Pompeu Fabra University in Spain; Centro de Analisis Genomico in Spain; Bilkent University in Turkey; Indiana Univeristy; Center for Cancer Research in Maryland; St. Petersburg State University in Russia; and Nova Southeastern University in Florida.

Source: Washington University in St. Louis

Study of mountain lion energetics shows the power of the pounce

The SMART wildlife collar is equipped with GPS, accelerometers, and a magnetometer to provide detailed data on where the animal is and what it is doing.

Scientists at UC Santa Cruz, using a new wildlife tracking collar they developed, were able to continuously monitor the movements of mountain lions in the wild and determine how much energy the big cats use to stalk, pounce, and overpower their prey.

The research team's findings, published October 3 in Science, help explain why most cats use a "stalk and pounce" hunting strategy. The new "SMART" wildlife collar--equipped with GPS, accelerometers, and other high-tech features--tells researchers not just where an animal is but what it is doing and how much its activities "cost" in terms of energy expenditure.

"What's really exciting is that we can now say, here's the cost of being a mountain lion in the wild and what they need in terms of calories to live in this environment," said first author Terrie Williams, a professor of ecology and evolutionary biology at UC Santa Cruz. "Understanding the energetics of wild animals moving in complex environments is valuable information for developing better wildlife management plans."

The researchers were able to quantify, for example, the high energetic costs of traveling over rugged terrain compared to the low cost of "cryptic" hunting behaviors such as sit-and-wait or stalk-and-ambush movements. During the actual pounce and kill, the cats invest a lot of energy in a short time to overpower their prey. Data from the collars showed that mountain lions adjust the amount of energy they put into the initial pounce to account for the size of their prey.

"They know how big a pounce they need to bring down prey that are much bigger than themselves, like a full-grown buck, and they'll use a much smaller pounce for a fawn," Williams said.

Cats on treadmills

Before Williams and her team could interpret the data from collars deployed on wild mountain lions, however, they first had to perform calibration studies with mountain lions in captivity. This meant, among other things, training mountain lions to walk and run on a treadmill and measuring their oxygen consumption at different activity levels. Those studies took a bit longer than planned.

"People just didn't believe you could get a mountain lion on a treadmill, and it took me three years to find a facility that was willing to try," Williams said.

Finally, she met Lisa Wolfe, a veterinarian with Colorado Parks and Wildlife, who had three captive mountain lions (siblings whose mother had been killed by a hunter) at a research facility near Fort Collins, Colorado. After eight months of training by Wolfe, the mountain lions were comfortable on the treadmill and Williams started collecting data.

Power animals

According to Williams, the treadmill data showed that mountain lions do not have the aerobic capacity for sustained, high-energy activity. "They are power animals. They have a slow routine walking speed and use a burst of speed and the force of the pounce to knock down or overpower their prey," she said.

In addition to the treadmill studies, the captive cats were videotaped wearing the collars while doing a wide range of activities in a large outdoor enclosure. This provided a library of collar acceleration signatures specific for different behaviors, from resting and grooming to running and pouncing. "We got all the different behaviors videotaped and analyzed with the corresponding accelerometer traces," Williams said.

Meanwhile, coauthor Chris Wilmers led a team that deployed the collars on wild cats in the Santa Cruz mountains. Wilmers, an associate professor of environmental studies at UC Santa Cruz, leads the Santa Cruz Puma Project, which has been tracking mountain lions in the area to study the effects of habitat fragmentation and developing new technology for understanding the animals' behavior and energetics.

"Because mountain lions are a cryptic animal, we can't really observe them hunting and killing prey. With the SMART collars, we can see how they go about doing that, what their strategies are, and how many calories they are expending to do it," Wilmers said. "The ability to estimate the field energetics of animals in the wild opens up a whole new suite of questions we can ask about the ecology of these animals, which ultimately informs not only our basic understanding of them but also their conservation and management."

State-of-the-art collars

Coauthor Gabriel Elkaim, professor of computer engineering at UCSC's Baskin School of Engineering, worked on signal processing of the accelerometer data and is continuing to develop the state-of-the-art tracking collars. The prototype used in this study, called the Species Movement, Acceleration, and Radio Tracking (SMART) wildlife collar, was developed by computer engineering graduate student Matthew Rutishauser. The collars include a GPS unit, accelerometers, and a magnetometer to provide detailed data on where an animal is and what it is doing. "We hope this will be an enabling technology to allow a much greater depth of understanding of animals in the wild," Elkaim said.

The researchers now want to look at mountain lion energetics in a range of different habitat types. In particular, Wilmers said, he is interested in how human land use and habitat fragmentation may be influencing the energetic demands on mountain lions in the wild. Williams and her students also have projects using the new collar technology to study other large carnivores, including wolves, polar bears, and Weddell seals.

"A lot of these large carnivore species are threatened or endangered, and understanding their physiological limitations has been a big missing piece in conservation planning," Williams said. "This technology gives us a whole new level understanding of what these animals are doing and what it costs them to live in the wild, and that can really help move the science of conservation forward."

In addition to Williams, Wilmers, Wolfe, and Elkaim, the coauthors of the paper include Tracy Davis at Colorado Parks and Wildlife; program manager Traci Kendall and head trainer Beau Richter in Williams's lab at UC Santa Cruz; and UCSC graduate students Yiwei Wang and Caleb Bryce. This research was funded by the National Science Foundation.

Source: University of California - Santa Cruz

On a safari through the genome: Genes offer new insights into the distribution of giraffes

Three young, male Angola giraffes. Credit: © Julian Fennessy, GCF

The Giraffe (Giraffa camelopardalis), a symbol of the African savanna and a fixed item on every safari's agenda, is a fascinating animal. However, contrary to many of the continent's other wild animals, these long-necked giants are still rather poorly studied. Based on their markings, distribution and genome, nine subspecies are recognized -- including the two subspecies Angola Giraffe (Giraffa c. angolensis) and South African Giraffe (Giraffa c. giraffa).

South African Giraffes occur farther north than previously assumed

Like most other giraffes, these subspecies are now mainly found in nature reserves. Until recently, scientists assumed a clear demarcation of their ranges: Angola Giraffes occur in Namibia and northern Botswana, while South African Giraffes reside in southern Botswana and South Africa. "However, according to our studies, the distribution areas prove to be much more complex. South African Giraffes also occur in northeastern Namibia and northern Botswana, and Angola Giraffes can be found in northwestern Namibia and southern Botswana, as well," explains the study's author, Friederike Bock from the Biodiversity and Climate Research Center (BiK-F). A look at the new distribution map reveals the presence of a population of Angola Giraffes in the Central Kalahari Game Reserve, the world's second-largest national park, quasi nestled between two populations of the South African Giraffe, with both subspecies living side by side.

Subspecies were the result of early geographic separation

According to the research team, the fact that two genetically distinct subspecies could develop within the same region may be explained by the local geographic conditions that prevailed approximately 500,000 to two million years ago. Back then, the mountain range along the East African Rift Valley was sinking, creating vast wetlands and lakes, such as the paleo lake Makgadikgadi. According to Professor Dr. Axel Janke from the BiK-F, "these large bodies of water may have separated the populations for long periods of time. Moreover, female giraffes likely do not migrate across long distances, thereby contributing to a clear separation of the maternal lines." Today, there no longer exist any barriers that prevent the possible mingling of both subspecies; an investigation of these processes is however subject to further genetic analyses.

Angola and South African Giraffes can be uniquely identified by their maternal gene profile

For the study, the researchers created a profile of the subspecies' mitochondrial DNA, using tissue samples from about 160 giraffes from various populations across the entire African continent. On the basis of this genetic material, inherited from the maternal side, the often similarly marked subspecies can be uniquely identified genetically and the relationships between various populations can be clearly demonstrated. "Our focus was on giraffes in southern Africa, in particular in Botswana and South Africa. There, we sampled populations that had not been genetically analyzed before," says Bock.

New insights enable improved protection measures for the giraffe

According to estimates by the World Conservation Organization IUCN, the world's giraffe population is about 100,000 individuals -- showing a decreasing trend. In Botswana alone, the population has dwindled by more than half in recent years. In order to achieve effective protection measures that will preserve the majority of the giraffe's subspecies, it is indispensable to gain knowledge that allows their reliable identification as well as detailed information regarding their distribution. The surprising results concerning the distribution of the two subspecies in Namibia and Botswana emphasize the importance of additional taxonomic research on all giraffe subspecies.

Source: Senckenberg Research Institute and Natural History Museum

Arctic conditions may become critical for polar bears by end of 21st century

This is a photo of an Arctic polar bear. Shifts in the timing and duration of ice cover, especially the possible lengthening of ice-free periods, may impact polar bears under projected warming before the end of the 21st century, according to a study published Nov. 26, 2014 in the open-access journal PLOS ONE by Stephen Hamilton from University of Alberta and colleagues. Credit: Andrew Derocher; CC-BY

Shifts in the timing and duration of ice cover, especially the possible lengthening of ice-free periods, may impact polar bears under projected warming before the end of the 21st century, according to a study published November 26, 2014 in the open-access journal PLOS ONE by Stephen Hamilton from University of Alberta and colleagues.

Sea ice across the Arctic is declining and altering physical characteristics of marine ecosystems, and polar bears are vulnerable to these changes in sea ice conditions. The authors of this study used sea ice projections for the Canadian Arctic Archipelago from 2006-2100 and metrics developed from polar bear energetics modeling to gain insight into the conservation challenges for polar bears facing habitat loss.

Shifts away from multiyear ice to annual ice cover throughout the region, as well as lengthening ice-free periods, may become critical for polar bears before the end of the 21st century with projected warming. Each polar bear population in the Archipelago may undergo 2-5 months of ice-free conditions, where no such conditions exist presently. Under business-as-usual climate projections, polar bears may face starvation and reproductive failure across the entire Archipelago by the year 2100. "We predict that nearly one-tenth of the world's polar bear habitat, as much as one-quarter of their global population, may undergo significant habitat loss under business-as-usual climate projections," said Stephen Hamilton.

Source: PLOS