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Red Fox - Vulpes vulpes
Journal Reference:
O’Malley C, Elbroch LM, Lendrum PE, Quigley H. (2018) Motion-triggered video cameras reveal spatial and temporal patterns of red fox foraging on carrion provided by mountain lions. PeerJ 6:e5324

Carrion is a rich, ephemeral resource vital to biodiversity and ecosystem health. In temperate ecosystems in which cold temperatures and snowfall influence the accessibility and availability of small prey and seasonal mast crops, carrion may also be a limiting resource for mesocarnivores like red foxes (Vulpes vulpes), which are too small to predate ungulates. Using motion-triggered video cameras and generalized linear mixed models, we studied the spatial and temporal patterns of red fox scavenging at 232 mountain lion kills in the southern Greater Yellowstone Ecosystem (GYE) from 2012–2015. We found that red foxes scavenged mountain lion kills across all habitats throughout the year, however, red fox behaviors varied with season. In winter, we documented red foxes at a greater proportion of mountain lion kills (70.3% in winter vs. 48.9% in summer), and in greater numbers (1.83 foxes per kill in winter vs. 1.16 in summer). In winter, red foxes fed longer (= 102.7 ± 138.3 minutes feeding in winter vs. = 39.7 ± 74.0 in summer), and they more often scavenged while the mountain lion was nearby. We speculated that red foxes may have increased risk taking in winter due to hunger driven by resource scarcity. Our research highlighted an important ecological relationship between red foxes and mountain lions in the GYE. Mountain lions tolerate high levels of scavenging, so the frequency and intensity of red fox scavenging at their kills may not impact mountain lions, but instead facilitate the dispersion and benefits of resources created by this apex predator. Large carnivores, and mid-trophic felids like mountain lions in particular, are essential producers of carrion vital to biodiversity and ecosystem health. In turn, scavengers play critical roles in distributing these resources and increasing the heterogeneity of resources that support biodiversity and ecosystem structure, as well as ecological resilience.

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Figure 1: A red fox carries away a large portion of mule deer carcass, a summer prey killed by an adult female mountain lion in the southern Greater Yellowstone Ecosystem.

Red fox caching aids in dispersing carrion resources, increasing the contributions of this apex predator to its larger ecological community. Photograph by L Mark Elbroch.
DOI: 10.7717/peerj.5324/fig-1

[Image: fig-3-1x.jpg]
Figure 3: A red fox awaiting the departure of a mountain lion so it can feed at the kill.

Despite occasionally falling prey to mountain lions, red foxes often fed in close proximity to the large predator, especially during winter months. Photograph by L Mark Elbroch.
DOI: 10.7717/peerj.5324/fig-3

Full Study:
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  • Claudiu Constantin Nicolaescu
Silver fox study reveals genetic clues to social behavior

Date:  September 27, 2018
Source:  Cornell University
After more than 50 generations of selective breeding, a new study compares gene expression of tame and aggressive silver foxes in two areas of the brain, shedding light on genes responsible for social behavior.

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A silver fox bred for tameness at the the Institute for Cytology and Genetics in Novosibirsk, Russia.
Credit: Darya Shepeleva

In 1959, Russian scientists began an experiment to breed a population of silver foxes, selecting and breeding foxes that exhibited friendliness toward people. They wanted to know if they could repeat the adaptations for tameness that must have occurred in domestic dogs. Subsequently they also bred another population of foxes for more aggressive behavior.
After 10 generations, a small fraction of the tame-bred foxes displayed dog-like domesticated behavior when people approached. Over time, an increasing fraction of the foxes showed this friendly behavior.
Now, after more than 50 generations of selective breeding, a new Cornell University-led study compares gene expression of tame and aggressive silver foxes in two areas of the brain, shedding light on genes responsible for social behavior.
The study, published online Sept. 18 in the Proceedings of the National Academy of Sciences, identified genes that were altered in tame animals in two areas of the brain involved with learning and memory.
"That such a radical change in temperament could be accomplished so quickly is truly remarkable," said Andrew Clark, professor in the Department of Molecular Biology and Genetics at Cornell and a senior co-author of the paper.
The research team obtained prefrontal cortex and basal forebrain brain tissue samples of 12 tame and 12 aggressive foxes from the Institute for Cytology and Genetics in Novosibirsk, Russia, where the foxes were bred.
Clark and first author Xu Wang, Ph.D., a former research associate in Clark's lab, conducted two types of genetic analysis. In one investigation, they sequenced the RNA produced by all genes, which allowed them to measure how much every gene was turned on. The other test identified different versions of genes, called alleles, and measured how they changed in frequency in the population over generations.
These analyses revealed which brain pathways were altered by breeding tame and aggressive foxes. The prefrontal cortex and basal forebrains are known for handling higher processing of information, including higher-level social interaction. The team was especially interested in neurons classified by the neurotransmitters (brain signaling chemicals) they release: dopamine, serotonin and glutamine.
The pleasure centers in the brain are triggered by dopamine, and Clark said he expected those dopaminergic pathways to be altered in the tame animals.
"Tame animals seem like they are blissed out all the time," he said. "They're just so happy and adorable, so I thought certainly the dopaminergic [pathway would be affected]. But there was no signal."
However, the genes that impact the function of both serotonergic neurons and glutaminergic neurons were clearly affected by selection toward tameness. These neurons are important for learning and memory.
Also, the analyses implicated genes important in the function of the neural crest, a transient group of cells that arises very early in the embryo. These cells migrate to form many types of adult cells, including those that determine skin and hair pigment (melanocytes), peripheral nerves, and the tissues of the face. The signals suggest a link to "domestication syndrome," a cluster of ancillary traits -- white fur spots, shorter nose, curly tail and floppy ears -- that pops up in domesticated canines, and in similar forms of other species.
"Darwin, and many others since, observed that when people select for domestication, there is a tendency to see a reversion in these traits to a more juvenile form," Clark said, adding that more study of the neural crest's role in domestication syndrome is needed.
The paper was written in tandem with another related study recently published in Nature Ecology and Evolution (NEE) that includes many of the same co-authors, including Clark, Wang, Lyudmila Trut, co-director at the Institute for Cytology and Genetics, and Anna Kukekova, the NEE paper's first author and an assistant professor in the Department of Animal Sciences at the University of Illinois. Kukekova has worked with Trut's lab in Novosibirsk, and is a former research scientist at Cornell's Baker Institute for Animal Health.

Story Source: Cornell University. "Silver fox study reveals genetic clues to social behavior." ScienceDaily. (accessed September 28, 2018).

Journal Reference:
  1. Xu Wang, Lenore Pipes, Lyudmila N. Trut, Yury Herbeck, Anastasiya V. Vladimirova, Rimma G. Gulevich, Anastasiya V. Kharlamova, Jennifer L. Johnson, Gregory M. Acland, Anna V. Kukekova, Andrew G. Clark. Genomic responses to selection for tame/aggressive behaviors in the silver fox (Vulpes vulpes). Proceedings of the National Academy of Sciences, 2018; 201800889 DOI: 10.1073/pnas.1800889115
Animal domestication efforts have led to a shared spectrum of striking behavioral and morphological changes. To recapitulate this process, silver foxes have been selectively bred for tame and aggressive behaviors for more than 50 generations at the Institute for Cytology and Genetics in Novosibirsk, Russia. To understand the genetic basis and molecular mechanisms underlying the phenotypic changes, we profiled gene expression levels and coding SNP allele frequencies in two brain tissue specimens from 12 aggressive foxes and 12 tame foxes. Expression analysis revealed 146 genes in the prefrontal cortex and 33 genes in the basal forebrain that were differentially expressed, with a 5% false discovery rate (FDR). These candidates include genes in key pathways known to be critical to neurologic processing, including the serotonin and glutamate receptor pathways. In addition, 295 of the 31,000 exonic SNPs show significant allele frequency differences between the tame and aggressive populations (1% FDR), including genes with a role in neural crest cell fate determination.
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  • Claudiu Constantin Nicolaescu
(07-14-2018, 04:55 PM)Taipan Wrote:
Red Dog Wrote:From Reddhole:

Quote:Interactions between Arctic and Red Foxes in Scandinavia - Predation and Aggression
"ABSTRACT. Arctic fox (Alopex lagopus) populations in Scandinavia are small and restricted to alpine regions, while red foxes (Vulpes vulpes) are common throughout both Norway and Sweden. The two species are similar in behaviour and diet, and thus competition between them is likely. This study provides seven observations of aggressive interactions between the two species. One adult arctic fox and one cub were killed by red foxes, one male arctic fox was chased away from his den, one female arctic fox and a cub fled into the den as a red fox approached, four cubs fled into the den as a red fox walked upon it and once a red fox walked upon the arctic fox den when no arctic foxes could be seen. Only on one occasion did an arctic fox succeed in chasing away a red fox. Red fox predation may prove to be limiting to the small arctic fox population in Scandinavia, and arctic foxes can be displaced from good dens and the most productive regions."

Below is an account constant with the above study where a red fox kills an arctic fox. The red fox kills the arctic fox within 10 seconds of engaging it. IMHO, this shows that canids can kill other animals fairly quickly considering that the red fox has a weak bite relative to other canids. The red fox seems to make up for this by having decently long canines and a good killing technique.

In November 2004, a red fox was observed chasing an
arctic fox under parked trucks and a nearby building
constructed on stilts. As the chase proceeded, the red fox
continued to gain on the arctic fox until contact was made,
at which point video shots were taken to document the
encounter. Six video clips totaling 2 minutes 36 seconds
were taken of the interaction.

The first video clip shows the two animals fighting. The
red fox was maintaining a superior position with respect to
the arctic fox, while trying to roll the arctic fox over in
repeated attempts to bite its neck. The arctic fox, struggling
underneath the red fox, was kicking and biting at it
(Fig. 1). At the 10-second mark of the video, the red fox
succeeded in biting the neck of the arctic fox and then
shook its head quickly from side to side, instantly killing
or paralyzing the arctic fox. The red fox proceeded to carry
the limp carcass across a parking lot and onto an adjacent
patch of undisturbed snow (Fig. 2). The last three video
clips show the red fox biting at the back of the arctic fox
just behind the shoulders, in what seemed to be attempts to
break open the skin (Fig. 3).

[Image: RedFoxKillingArcticFox001.jpg]

FIG. 1. Red and arctic fox fighting, with red fox maintaining a superior position.

[Image: RedFoxKillingArcticFox002.jpg]

FIG. 2. The red fox carrying the carcass of the arctic fox away from the kill site. Prudhoe Bay oilfield, Alaska, November 2004.

[Image: RedFoxKillingArcticFox003.jpg]

FIG. 3. The red fox biting and chewing at the back of the arctic fox, just posterior to the shoulders, after carrying the carcass off from the kill site.

Apparently this is not that uncommon:

We have had many conversations with oilfield personnel
during which they reported on similar encounters
between red and arctic foxes. Most encounters reported
involve red foxes chasing arctic foxes, but some report
arctic foxes being killed and consumed.

Catboy Wrote:
Sicilianu Wrote:Red fox>arctic fox>gray fox

More evidence of the first part:

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To the victor the spoils. An image of warring foxes has won the 2015 Wildlife Photographer of the Year competition.
Taken by amateur Don Gutoski, the picture captures the moment a red fox hauls away the carcass of its Arctic cousin following a deadly attack in Canada's Wapusk National Park.
"It's the best picture I've ever taken in my life," Don told BBC News.
"It's the symmetry of the heads, the bodies and the tails - even the expression on the faces."
The two animals' ranges overlap at Wapusk, which hugs the shore of Hudson Bay in Manitoba.
And if the larger red catches sight of the Arctic resident, it will try to predate the northern species.
Wildlife guides in the park had spoken of seeing the conflict, but this is thought to be one of the first cases where it has been documented on camera.
Kathy Moran, who sat on the judging panel, said the horror of the scene was surprisingly understated.
"It doesn't come across as gory at all. If fact, when you first look at the picture - it's almost as if the red fox is taking off his winter coat."
Kathy, who is National Geographic magazine's senior editor for natural history projects, also described it as an image with a powerful message about climate change.
"As it gets warmer in the Arctic and sub-Arctic and the red fox can move further north into the territory occupied by the Arctic fox, you are going to get increasingly these kinds of tensions," she said.
Don Gutoski was named as Wildlife Photographer of the Year (WPY) on Tuesday, at a ceremony at London's Natural History Museum. The NHM owns and organises the competition.
The judges sorted through 42,000 entries submitted from almost 100 countries.
"A Tale of Two Foxes", as the winning image is known, will now feature in an exhibition that will open at the museum on Friday before, at a later date, going on tour.

(06-03-2019, 12:59 PM)K9Boy Wrote: Red Fox kills Arctic Fox

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  • Claudiu Constantin Nicolaescu

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