Joined: February 11th, 2012, 7:29 am

January 31st, 2015, 4:47 am #31

Rarely Seen Saharan Cheetah Revealed in Incredible Photos

By John R. Platt | January 30, 2015 |



It’s not easy to get a glimpse of the critically endangered Saharan cheetah (Acinonyx jubatus hecki), the rarest of the six cheetah subspecies. Only about 200 to 250 of these nocturnal cats are thought to survive in remote pockets of Algeria, Niger, Togo, Mali, Benin and Burkina Faso, making them the rarest—and at the same time the most widely distributed—large predator on the planet.

But now a team of scientists working in Algeria has managed to capture not just an image of a single Saharan cheetah, but more than two dozen. In the process, the team has gathered the first real scientific information about these big cats.



“This is the first time we have been able to collect scientific data on the rare Saharan cheetah, as in the past we have had to rely on anecdotes and guesswork,” lead author Farid Belbachir from Laboratoire d’Ecologie et Environnement, Université de Béjaïa, Algeria, said in a prepared statement. “We hope that this important carnivore does not follow the path to extinction like other Algerian desert species such as the addax antelope and dama gazelle.”

The research team—which included scientists from the Wildlife Conservation Society, the Zoological Society of London and other institutions—spent several months in Algeria in 2008 and 2010. There, they set up hundreds of camera traps which together operated a total of 5,229 days. During that time the cameras recorded a grand total of 32 photos of seven different cheetahs, each of which could be identified by its size and unique markings. Saharan cheetahs have paler, shorter fur than their savannah cousins, as well as smaller heads and thinner bodies.

All but two of the photos were captured after sunset and in the twilight hours before sunrise, which supported previous assumptions that the cats operate nocturnally.

The photos also revealed clues about the animals’ territory. The same cheetahs were photographed by different cameras up to 44.9 kilometers away from each other, indicating that the cats use an incredibly broad stretch of habitat. Although some images captured more than one cheetah at a time, they mostly live far away from each other. The researchers estimate that they live at lower densities than any other African carnivore.



The Saharan desert is not exactly rich with food or water for big cats, so they need wide ranges in order to hunt. This also explains their nocturnal behavior: it would be too hot to hunt and travel over such large distances during the day.

The researchers used the photographs to estimate that the cheetahs in Algeria have a home range of 1,583 square kilometers. Keeping them safe from humans would require even more space, between 9,000 and 19,000 square kilometers, depending on how much of a buffer zone could be created. The Sahara Conservation Fund posited several years ago that the cheetahs could be at risk if they started preying on livestock or other domesticated animals, which could result in the retaliatory use of poison to wipe them out. Night hunting with spotlights already threatens the other wildlife in the region and is responsible for the eradication of the two ungulate species, the addax antelope and dama gazelle, which Belbachir mentioned.

All of this has an end-point. The researchers wrote that using the Saharan cheetah as a “flagship species” could provide incentive to conserve their entire ecosystem.

Their research was published this week in the journal PLOS ONE.

http://blogs.scientificamerican.com/ext ... -revealed/

Monitoring Rarity: The Critically Endangered Saharan Cheetah as a Flagship Species for a Threatened Ecosystem

Farid Belbachir, Nathalie Pettorelli, Tim Wacher, Amel Belbachir-Bazi, Sarah M. Durant
Published: January 28, 2015DOI: 10.1371/journal.pone.0115136

Abstract
Deserts are particularly vulnerable to human impacts and have already suffered a substantial loss of biodiversity. In harsh and variable desert environments, large herbivores typically occur at low densities, and their large carnivore predators occur at even lower densities. The continued survival of large carnivores is key to healthy functioning desert ecosystems, and the ability to gather reliable information on these rare low density species, including presence, abundance and density, is critical to their monitoring and management. Here we test camera trap methodologies as a monitoring tool for an extremely rare wide-ranging large felid, the critically endangered Saharan cheetah (Acinonyx jubatus hecki). Two camera trapping surveys were carried out over 2–3 months across a 2,551km2 grid in the Ti-n-hağğen region in the Ahaggar Cultural Park, south central Algeria. A total of 32 records of Saharan cheetah were obtained. We show the behaviour and ecology of the Saharan cheetah is severely constrained by the harsh desert environment, leading them to be more nocturnal, be more wide-ranging, and occur at lower densities relative to cheetah in savannah environments. Density estimates ranged from 0.21–0.55/1,000km2, some of the lowest large carnivore densities ever recorded in Africa, and average home range size over 2–3 months was estimated at 1,583km2. We use our results to predict that, in order to detect presence of cheetah with p>0.95 a survey effort of at least 1,000 camera trap days is required. Our study identifies the Ahaggar Cultural Park as a key area for the conservation of the Saharan cheetah. The Saharan cheetah meets the requirements for a charismatic flagship species that can be used to “market” the Saharan landscape at a sufficiently large scale to help reverse the historical neglect of threatened Saharan ecosystems.

http://journals.plos.org/plosone/articl ... ne.0115136
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September 16th, 2015, 5:27 am #32

Brave cheetah defied torture to rear 20 cubs as she graced her African grasslands

CONSERVATIONISTS have been left heartbroken after the big cat that overcame appalling adversity as a youngster died after being hurt during a hunting foray.


By STUART WINTER
PUBLISHED: 18:19, Tue, Sep 15, 2015 | UPDATED: 18:20, Tue, Sep 15, 2015


Sibella in the African grassland she called home
Amazingly, Sibella had defied the laws of nature to still be chasing prey at the grand old age of 14, especially when she almost never made it past her second year after being treated appallingly by hunters.

In her final hunt, she was left with a gaping hole in her abdomen after trying to catch a duiker, a small type of antelope. Despite the best effort of a vet, she died a few hours after being wounded.


Sibella raised 20 cubs during her lifetime
But Sibella's incredible legacy is the four litters of cubs she produced to ensure cheetahs still bring their guile, speed and beauty to South Africa's Great Karoo region.

Sibella was the first wild cheetah reintroduced to the region in more than than a century when she was released on to the Samara Private Game Reserve near Graaff-Reinet in December 2003.

That chapter of her life began after she had almost been killed by hunters. Set upon by dogs that tore the flesh from her hind legs, she was savagely beaten and locked in a cage.

As she hovered at death's door, Sibella was fortunately rescued by the De Wildt Cheetah and Wildlife Trust. Five hours of surgery and rehabilitation meant she was ready again for the wild.

As Sarah Tompkins, director of the Samara Private Game Reserve, explains: "Since then, she has surpassed all expectations, outliving most cheetah in the wild. She has proved herself to be a capable hunter despite her previous injuries.

"Rearing an astonishing 20 cubs in four litters since her release proves she has been an exemplary mother, giving birth on steep mountain slopes to avoid potential predators and eating only after her young have had their fill.

"The unspoken bond she shared with the humans in her new home was extraordinary - with the birth of each new litter, when the cubs were old enough to leave their den, this wild cat dutifully presented to her human guardians her latest bundles of fur.


Sibella watches over one of her cubs

"The degree of trust she vested in human beings, walking to within just a few metres of them, was simply astounding, her past suffering at the hands of her tormentors all but forgotten.

"Sibella's story, from tortured to treasured, is symbolic of the change in mindset required to conserve our planet's biodiversity.

"We mourn her loss but seek comfort in knowing that she lived and died in a wild environment. We feel incredibly privileged to have been witness to the life of this exceptional cat."

http://www.express.co.uk/news/nature/60 ... grasslands
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December 11th, 2015, 6:32 am #33

Cheetahs migrated from North America

Date: December 8, 2015
Source: BioMed Central
Summary:
The cheetah (Acinonyx jubatus) is now at home on the African plains, but it started a migration 100,000 years ago from North America towards its current habitat. The research found that the migration from North America was costly for the species, triggering the first major reduction in their gene pool.


Cheetah on the Masai Mara in Africa (stock image). The cheetah is descended from a relative of American pumas and their fossil record extends across the Americas, Europe and Asia.
Credit: © Bryan Busovicki / Fotolia

The cheetah (Acinonyx jubatus) is now at home on the African plains, but it started a migration 100, 000 years ago from North America towards its current habitat. The research, published in the open access journal Genome Biology, found that the migration from North America was costly for the species, triggering the first major reduction in their gene pool.

The modern African cheetah is found across eastern and southern Africa, but it is highly endangered because of their small free ranging population and inbreeding. Researchers from St. Petersburg State University, Russia, in collaboration with BGI, China and CCF, Namibia, sequenced the genome from a male Namibian cheetah, called 'Chewbaaka', and six other wild cheetahs from Tanzania and Namibia. This gave further insight into the species evolutionary history and the breadth of genome impoverishment, which elevates juvenile mortality, causes extreme abnormalities in sperm development and increases vulnerability to infectious disease outbreaks.

A total of 18 cheetah genes showed damaging mutations and one gene in particular, AKAP4, showed a large number of mutations, which could harm sperm development and may explain why cheetah have a large proportion of defective sperm, and hence their low reproductive success.

The cheetah is descended from a relative of American pumas and their fossil record extends across the Americas, Europe and Asia. The species has suffered two population bottlenecks -- an event whereby the population is rapidly reduced due to environmental factors.

The first of these took place 100, 000 years ago, around the late Pleistocene -- a geological period shaped by repeated glaciations, when cheetahs started to move towards Asia across the Beringian landbridge and then travelled south to Africa. This migration was punctuated with dwindling populations and limited gene flow due to the individuals' own vast territory boundaries, measuring 300-800 square miles, thereby increasing incestuous mating.

The second bottleneck around 10- 12, 000 years ago, further reduced numbers, leading to further loss of endemic variability observed in modern cheetahs. This is because cheetahs disappeared from North America, when the last glacial retreat caused an abrupt extinction resulting in the loss of many large mammals, including cheetahs and pumas, from North America.

Cheetahs accept skin grafts from unrelated cheetahs as if they were clones. The genome analysis suggests that this is partly due to the loss of a few immune related genes and dramatic loss of diversity in the cheetahs' flagella genes. The variation is so limited that it is far below that observed in inbred dogs and cats. Tests carried out by the researchers show that the cheetah has lost 90-99% of the genetic variation typically seen in outbred mammals.

The researchers conclude that this latest insight into the history and adaptation of the endangered cheetah should be useful in efforts to sustain and increase cheetah population numbers in their present and former range habitats.

Story Source: BioMed Central. "Cheetahs migrated from North America." ScienceDaily. www.sciencedaily.com/releases/2015/12/151208204222.htm (accessed December 11, 2015).

Journal Reference:
Dobrynin et al. Genomic legacy of the African cheetah, Acinonyx jubatus. Genome Biology, December 2015 DOI: 10.1186/s13059-015-0837-4

Abstract
Background
Patterns of genetic and genomic variance are informative in inferring population history for human, model species and endangered populations.
Results
Here the genome sequence of wild-born African cheetahs reveals extreme genomic depletion in SNV incidence, SNV density, SNVs of coding genes, MHC class I and II genes, and mitochondrial DNA SNVs. Cheetah genomes are on average 95 % homozygous compared to the genomes of the outbred domestic cat (24.08 % homozygous), Virunga Mountain Gorilla (78.12 %), inbred Abyssinian cat (62.63 %), Tasmanian devil, domestic dog and other mammalian species. Demographic estimators impute two ancestral population bottlenecks: one >100,000 years ago coincident with cheetah migrations out of the Americas and into Eurasia and Africa, and a second 11,084–12,589 years ago in Africa coincident with late Pleistocene large mammal extinctions. MHC class I gene loss and dramatic reduction in functional diversity of MHC genes would explain why cheetahs ablate skin graft rejection among unrelated individuals. Significant excess of non-synonymous mutations in AKAP4 (p80 %) pleiomorphic sperm.
Conclusions
The study provides an unprecedented genomic perspective for the rare cheetah, with potential relevance to the species’ natural history, physiological adaptations and unique reproductive disposition.


http://www.genomebiology.com/2015/16/1/277
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May 5th, 2016, 7:41 am #34

Estimates of cheetah numbers are 'guesswork,' say researchers

Date: May 3, 2016
Source: University of Oxford


The female cheetah with her cubs (stock image). The results of this study will allow threats and conservation efforts to be quantified and monitored in the future.
Credit: © gudkovandrey / Fotolia

Current estimates of the number of cheetahs in the wild are 'guesswork', say the authors of a new study which finds that the population in the cheetah stronghold of Maasai Mara, Kenya, is lower than previously thought.

In the early 1900s it was believed that around 100,000 cheetahs roamed Earth. The most recent estimate by the International Union for Conservation of Nature (IUCN) puts the figure at 6,600 -- mainly in eastern and southern Africa -- amid fears that the fastest land mammal is racing to extinction.

However, a team of scientists from the Kenya Wildlife Trust's Mara Cheetah Project, the University of Oxford and the Indian Statistical Institute says this number is simply a best guess, given the difficulty of counting cheetahs accurately.

The researchers have now developed a new method to accurately count cheetahs, which in time will help determine the magnitude of the threats they face and assess potential conservation interventions.

The study is published in the journal PLOS ONE.

Lead author Dr Femke Broekhuis, Project Director of the Mara Cheetah Project and a post-doctoral researcher at the Wildlife Conservation Research Unit (WildCRU), Department of Zoology, University of Oxford, said: 'The truth is that estimates of cheetah numbers are only best guesses, because cheetahs are a lot harder to count accurately than one might think. They naturally occur at low densities and move large distances, making them difficult to find.

'Whatever the exact number, we do know that they are extinct in 20 countries and occupy only 17% of their historical range. We also know the major threats facing cheetahs: habitat loss, human-wildlife conflict, depleting prey and the illegal pet trade.

'What we have lacked until now is a way to assess whether or not conservation efforts are effective.'

During a three-month period, researchers in five vehicles extensively covered the Maasai Mara National Reserve and surrounding wildlife conservancies in search of cheetahs. The field team photographed each cheetah that was seen and identified each individual based on its unique coat pattern. These data were then analysed using an advanced Bayesian Spatially Explicit Capture Recapture (SECR) statistical model. This technique, incorporating information such as identity and location, is more powerful than previous methods used to estimate cheetah numbers.

The study revealed an average of 1.28 adult cheetahs/100km2 in the Maasai Mara -- an average total of 30 animals. This number is lower than previously thought -- around half, in fact. The 'spatially explicit' method used can distinguish 'visiting' animals from those that reside permanently within the surveyed area, avoiding potential overestimation. The researchers compare this to counting the population of Manhattan in the daytime, which would give a vastly inflated figure because of the influx of commuters from neighbouring areas.

The researchers also identified clear cheetah 'hotspots' within the Maasai Mara. The next step is to determine how the distribution of these high-density areas is correlated with environmental variables such as habitat, prey, predators, or anthropogenic factors including livestock grazing.

The results of this study will allow threats and conservation efforts to be quantified and monitored in the future.

Dr Broekhuis said: 'In order to determine the impact that threats and conservation efforts are having on the cheetah population, it is necessary to rigorously monitor their numbers over time. Our results are therefore important, as they provide the baseline data needed to accomplish this.

'The relevance of this study goes beyond cheetahs in the Maasai Mara. This is the first time that this robust method has been used to estimate cheetah densities, and it is a method that can be applied to other areas and other charismatic species such as lions or even elephants.'

Co-author Dr Arjun Gopalaswamy, from the Indian Statistical Institute and the Department of Zoology at the University of Oxford, said: 'The method we have used accounts for detection probability and is therefore more accurate than other methods that are currently being used to estimate cheetah numbers. In addition, the modelling approach we have used allows for estimating not only abundance and density, which were of prime interest to us, but also provides vital information about adult sex ratios and sex-specific home range sizes.

'These measures provide crucial insights about big cat ecology that aids their conservation. For example, India has been considering the reintroduction of the African cheetah. Even in a prey-rich area like the Maasai Mara, the density of cheetahs is low, suggesting that the resource requirements for these cats are perhaps much larger than would be available currently in the Indian subcontinent.'

The study's authors say there is an urgent need to rigorously assess the population size of cheetahs in all the remaining strongholds, using advanced methods such as this one. They also suggest that relying merely on best guesses of cheetah numbers at regional levels can seriously mislead cheetah conservation efforts on the ground.

Story Source: University of Oxford. "Estimates of cheetah numbers are 'guesswork,' say researchers." ScienceDaily. www.sciencedaily.com/releases/2016/05/160503130350.htm (accessed May 5, 2016).

Journal Reference:
Femke Broekhuis, Arjun M. Gopalaswamy. Counting Cats: Spatially Explicit Population Estimates of Cheetah (Acinonyx jubatus) Using Unstructured Sampling Data. PLOS ONE, 2016; 11 (5): e0153875 DOI: 10.1371/journal.pone.0153875

Abstract
Many ecological theories and species conservation programmes rely on accurate estimates of population density. Accurate density estimation, especially for species facing rapid declines, requires the application of rigorous field and analytical methods. However, obtaining accurate density estimates of carnivores can be challenging as carnivores naturally exist at relatively low densities and are often elusive and wide-ranging. In this study, we employ an unstructured spatial sampling field design along with a Bayesian sex-specific spatially explicit capture-recapture (SECR) analysis, to provide the first rigorous population density estimates of cheetahs (Acinonyx jubatus) in the Maasai Mara, Kenya. We estimate adult cheetah density to be between 1.28 ± 0.315 and 1.34 ± 0.337 individuals/100km2 across four candidate models specified in our analysis. Our spatially explicit approach revealed ‘hotspots’ of cheetah density, highlighting that cheetah are distributed heterogeneously across the landscape. The SECR models incorporated a movement range parameter which indicated that male cheetah moved four times as much as females, possibly because female movement was restricted by their reproductive status and/or the spatial distribution of prey. We show that SECR can be used for spatially unstructured data to successfully characterise the spatial distribution of a low density species and also estimate population density when sample size is small. Our sampling and modelling framework will help determine spatial and temporal variation in cheetah densities, providing a foundation for their conservation and management. Based on our results we encourage other researchers to adopt a similar approach in estimating densities of individually recognisable species.

http://journals.plos.org/plosone/articl ... ne.0153875
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December 29th, 2016, 5:14 am #35

Sprinting towards extinction? Cheetah numbers crash globally
Scientists confirm just 7,100 cheetahs remain, call for uplisting to 'Endangered' on IUCN Red List


Date: December 26, 2016
Source: Panthera
Summary:
A new study confirms that the iconic cheetah is sprinting towards extinction.


Cheetah on a rock.
Credit: Zoological Society of London

The world's fastest land animal, the cheetah (Acinonyx jubatus), is sprinting towards the edge of extinction and could soon be lost forever unless urgent, landscape-wide conservation action is taken, according to a study published today in the journal Proceedings of the National Academy of Sciences.

Led by Zoological Society of London (ZSL), Panthera and Wildlife Conservation Society (WCS), the study reveals that just 7,100 cheetahs remain globally, representing the best available estimate for the species to date. Furthermore, the cheetah has been driven out of 91% of its historic range. Asiatic cheetah populations have been hit hardest, with fewer than 50 individuals remaining in one isolated pocket of Iran.

Due to the species' dramatic decline, the study's authors are calling for the cheetah to be up-listed from 'Vulnerable' to 'Endangered' on the IUCN Red List of Threatened Species. Typically, greater international conservation support, prioritization and attention are granted to wildlife classified as 'Endangered', in efforts to stave off impending extinction.

Dr. Sarah Durant, ZSL/WCS lead author and Project Leader for the Rangewide Conservation Program for Cheetah and African Wild Dog, said: "This study represents the most comprehensive analysis of cheetah status to date. Given the secretive nature of this elusive cat, it has been difficult to gather hard information on the species, leading to its plight being overlooked. Our findings show that the large space requirements for cheetah, coupled with the complex range of threats faced by the species in the wild, mean that it is likely to be much more vulnerable to extinction than was previously thought."

Durant continued, "We have worked with range state governments and the cheetah conservation community to put in place comprehensive frameworks for action to save the species, but funds and resources are needed to implement them. The recent decisions made at the CITES CoP17 meeting in Johannesburg represent a significant breakthrough particularly in terms of stemming the illegal flow of live cats trafficked out of the Horn of Africa region. However, concerted action is needed to reverse ongoing declines in the face of accelerating land use changes across the continent."

While renowned for its speed and spots, the degree of persecution cheetahs face both inside and outside of protected areas is largely unrecognized. Even within guarded parks and reserves, cheetahs rarely escape the pervasive threats of human-wildlife conflict, prey loss due to overhunting by people, habitat loss and the illegal trafficking of cheetah parts and trade as exotic pets.

To make matters worse, as one of the world's most wide-ranging carnivores, 77% of the cheetah's habitat falls outside of protected areas. Unrestricted by boundaries, the species' wide-ranging movements weaken law enforcement protection and greatly amplify its vulnerability to human pressures. Indeed, largely due to pressures on wildlife and their habitat outside of protected areas, Zimbabwe's cheetah population has plummeted from 1,200 to a maximum of 170 animals in just 16 years -- representing an astonishing loss of 85% of the country's cheetahs.

Scientists are now calling for an urgent paradigm shift in cheetah conservation, towards landscape-level efforts that transcend national borders and are coordinated by existing regional conservation strategies for the species. A holistic conservation approach, which incentivises protection of cheetahs by local communities and trans-national governments, alongside sustainable human-wildlife coexistence is paramount to the survival of the species.

Panthera's Cheetah Program Director, Dr. Kim Young-Overton, shared, "We've just hit the reset button in our understanding of how close cheetahs are to extinction. The take-away from this pinnacle study is that securing protected areas alone is not enough. We must think bigger, conserving across the mosaic of protected and unprotected landscapes that these far-ranging cats inhabit, if we are to avert the otherwise certain loss of the cheetah forever."

The methodology used for this study will also be relevant to other species, such as African wild dogs, which also require large areas of land to prosper and are therefore similarly vulnerable to increasing threats outside designated protected areas.

Story Source: Panthera. "Sprinting towards extinction? Cheetah numbers crash globally: Scientists confirm just 7,100 cheetahs remain, call for uplisting to 'Endangered' on IUCN Red List." ScienceDaily. www.sciencedaily.com/releases/2016/12/161226211232.htm (accessed December 28, 2016).

Journal Reference:
Sarah M. Durant, Nicholas Mitchell, Rosemary Groom, Nathalie Pettorelli, Audrey Ipavec, Andrew P. Jacobson, Rosie Woodroffe, Monika Böhm, Luke T. B. Hunter, Matthew S. Becker, Femke Broekhuis, Sultana Bashir, Leah Andresen, Ortwin Aschenborn, Mohammed Beddiaf, Farid Belbachir, Amel Belbachir-Bazi, Ali Berbash, Iracelma Brandao de Matos Machado, Christine Breitenmoser, Monica Chege, Deon Cilliers, Harriet Davies-Mostert, Amy J. Dickman, Fabiano Ezekiel, Mohammad S. Farhadinia, Paul Funston, Philipp Henschel, Jane Horgan, Hans H. de Iongh, Houman Jowkar, Rebecca Klein, Peter Andrew Lindsey, Laurie Marker, Kelly Marnewick, Joerg Melzheimer, Johnathan Merkle, Jassiel M'soka, Maurus Msuha, Helen O'Neill, Megan Parker, Gianetta Purchase, Samaila Sahailou, Yohanna Saidu, Abdoulkarim Samna, Anne Schmidt-Küntzel, Eda Selebatso, Etotépé A. Sogbohossou, Alaaeldin Soultan, Emma Stone, Esther van der Meer, Rudie van Vuuren, Mary Wykstra, and Kim Young-Overton. The global decline of cheetah Acinonyx jubatus and what it means for conservation. PNAS, December 27, 2016 DOI: 10.1073/pnas.1611122114

Abstract
Establishing and maintaining protected areas (PAs) are key tools for biodiversity conservation. However, this approach is insufficient for many species, particularly those that are wide-ranging and sparse. The cheetah Acinonyx jubatus exemplifies such a species and faces extreme challenges to its survival. Here, we show that the global population is estimated at ∼7,100 individuals and confined to 9% of its historical distributional range. However, the majority of current range (77%) occurs outside of PAs, where the species faces multiple threats. Scenario modeling shows that, where growth rates are suppressed outside PAs, extinction rates increase rapidly as the proportion of population protected declines. Sensitivity analysis shows that growth rates within PAs have to be high if they are to compensate for declines outside. Susceptibility of cheetah to rapid decline is evidenced by recent rapid contraction in range, supporting an uplisting of the International Union for the Conservation of Nature (IUCN) Red List threat assessment to endangered. Our results are applicable to other protection-reliant species, which may be subject to systematic underestimation of threat when there is insufficient information outside PAs. Ultimately, conserving many of these species necessitates a paradigm shift in conservation toward a holistic approach that incentivizes protection and promotes sustainable human–wildlife coexistence across large multiple-use landscapes.

http://www.pnas.org/content/early/2016/12/20/1611122114
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March 27th, 2017, 6:51 am #36

How cheetahs stay fit and healthy

Date: March 23, 2017
Source: Forschungsverbund Berlin e.V. (FVB)


Handling cheetahs an farmland in Namibia.
Credit: Bettina Wachter/Leibniz-IZW

Cheetahs are categorized as vulnerable species, partly because they have been considered to be prone to diseases due to their supposed weak immune system. However, they are hardly ever sick in the wild. A research team from the German Leibniz Institute for Zoo and Wildlife Research (IZW) recently discovered that cheetahs have developed a very efficient innate "first line of defense" immunity to compensate potential deficiencies in other components of their immune system. The scientists have published their results in the open access journal Scientific Reports of the Nature Publishing Group.

Cheetahs have a relatively low genetic variability which means that, within a population, the individuals have a similar genetic makeup. This is also true for the major histocompatibility complex (MHC), a genome region that regulates the so-called "adaptive" immune system and is typically highly variable in animal species. The adaptive immune system provides a rapid and specific defense against pathogens, if they have been encountered previously. A low MHC variability should therefore result in a weak adaptive immune system and thus a high vulnerability to diseases. This is often the case in species with low MHC variability, but there are some exceptions, the cheetah indeed being one of them. "During our long-term study that begun in 2002, we investigated more than 300 free-ranging cheetahs that live on farmland in Namibia. We did not encounter any cheetah with symptoms of acute infections, nor did we detect lesions in the examined dead animals," explains Bettina Wachter, head of the cheetah research project.

How can cheetahs cope so well with pathogens despite their supposedly weak adaptive immunity? The immune system is divided into three components:(1) the constitutive innate immune system, which provides a rapid first line of defense against intruders, (2) the induced innate immune system such as the local and systemic inflammatory response, which enhances recovery and decreases pathogen growth, and (3) the adaptive immune system.

"We decided to investigate all three components simultaneously, an approach that is rarely done although it is very promising. For every animal, a well-functioning immune system is associated with certain energetic costs. However, this does not imply that all immune components are equally strongly developed. If a species is not vulnerable to diseases, a good immune response must have evolved by strengthening other parts of the immune system," says Gábor Czirják, wildlife immunologist at the Leibniz-IZW.

To compare the results with another species, the scientists included leopards in the study. "Leopards live in the same habitat as cheetahs in Namibia, but they have a high variability in their MHC. Thus, leopards should have a strong adaptive immune system and might not invest that much energy in the other parts of the immune system," explains Wachter.

"We first needed to adapt six immunological tests from the toolbox of the wildlife immunology for the cheetah and leopard," explains Sonja Heinrich, first author of the study. "We conducted these tests at the laboratory of the Leibniz IZW, thus needed to transport the samples we collected in Namibia all the way to Germany, keeping the cooling chain uninterrupted from the captured animal in the field to the Leibniz IZW." The immunological tests confirmed that leopards have a stronger adaptive immune system than cheetahs, consistent with the differences in the MHC variability of both species. As expected, cheetahs had a stronger innate "first line of defense" immune system than leopards, thereby probably compensating their weak adaptive immune system.

The induced innate immune system reacts to pathogen intruders as well as to temporary stress. Therefore, the scientists also determined the concentration of the hormone cortisol, which activates catabolic processes and is increasingly released during stress. Although both species were exposed to the same capture and handling procedures leopards had significantly higher cortisol concentration in their blood than cheetahs, indicating that leopards reacted stronger to the examination methods. Thus, short-term stress might have stimulated the induced innate immune system, making it difficult to assess whether this immune part also helps to compensate the weak adaptive immune system of cheetahs, if the stress effect is not considered.

This is the first study in mammals demonstrating that different species spend varying efforts in the development of the different immune components. Cheetahs have apparently developed a way to successfully fight against pathogens despite their low genetic variability in their MHC. However, the future of this vulnerable species is highly uncertain because most of their habitat occurs in unprotected areas and they frequently come into conflicts with humans. Only if these conflicts can be mitigated, the cheetahs have a good chance to persist in the wild in the future.

Story Source: Forschungsverbund Berlin e.V. (FVB). "How cheetahs stay fit and healthy." ScienceDaily. www.sciencedaily.com/releases/2017/03/170323125947.htm (accessed March 26, 2017).

Journal Reference:
Sonja K. Heinrich, Heribert Hofer, Alexandre Courtiol, Jörg Melzheimer, Martin Dehnhard, Gábor Á. Czirják, Bettina Wachter. Cheetahs have a stronger constitutive innate immunity than leopards. Scientific Reports, 2017; 7: 44837 DOI: 10.1038/srep44837

Abstract
As a textbook case for the importance of genetics in conservation, absence of genetic variability at the major histocompatibility complex (MHC) is thought to endanger species viability, since it is considered crucial for pathogen resistance. An alternative view of the immune system inspired by life history theory posits that a strong response should evolve in other components of the immune system if there is little variation in the MHC. In contrast to the leopard (Panthera pardus), the cheetah (Acinonyx jubatus) has a relatively low genetic variability at the MHC, yet free-ranging cheetahs are healthy. By comparing the functional competence of the humoral immune system of both species in sympatric populations in Namibia, we demonstrate that cheetahs have a higher constitutive innate but lower induced innate and adaptive immunity than leopards. We conclude (1) immunocompetence of cheetahs is higher than previously thought; (2) studying both innate and adaptive components of immune systems will enrich conservation science.

http://www.nature.com/articles/srep44837
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Joined: February 11th, 2012, 7:29 am

February 3rd, 2018, 5:01 am #37

Cheetahs' inner ear is one-of-a-kind, vital to high-speed hunting

February 2, 2018, American Museum of Natural History


This illustration shows the location of the inner ear in a modern cheetah skull. Credit: © AMNH/N. Wong

The world's fastest land animal, the cheetah, is a successful hunter not only because it is quick, but also because it can hold an incredibly still gaze while pursuing prey. For the first time, researchers have investigated the cheetah's extraordinary sensory abilities by analyzing the speedy animal's inner ear, an organ that is essential for maintaining body balance and adapting head posture during movement in most vertebrates. The study, published today in the journal Scientific Reports and led by researchers at the American Museum of Natural History, finds that the inner ear of modern cheetahs is unique and likely evolved relatively recently.

"If you watch a cheetah run in slow motion, you'll see incredible feats of movement: its legs, its back, its muscles all move with such coordinated power. But its head hardly moves at all," said lead author Camille Grohé, who conducted this work during a National Science Foundation and Frick Postdoctoral Fellowship in the Museum's Division of Paleontology. "The inner ear facilitates the cheetah's remarkable ability to maintain visual and postural stability while running and capturing prey at speeds of up to 65 miles per hour. Until now, no one has investigated the inner ear's role in this incredible hunting specialization."

In the inner ear of vertebrates, the balance system consists of three semicircular canals that contain fluid and sensory hair cells that detect movement of the head. Each of the semicircular canals is positioned at a different angle and is especially sensitive to different movements: up and down, side-to-side, and tilting from one side to the other.

The researchers used high-resolution X-ray computed tomography (CT) at the Museum's Microscopy and Imaging Facility, the National Museum of Natural History in Paris, and the Biomaterials Science Center of the University of Basel in Switzerland to scan the skulls of 21 felid specimens, including seven modern cheetahs (Acinonyx jubatus) from distinct populations, a closely related extinct cheetah (Acinonyx pardinensis) that lived in the Pleistocene between about 2.6 million and 126,000 years ago, and more than a dozen other living felid species. With those data, they created detailed 3-D virtual images of each species' inner ear shape and dimensions.

They found that the inner ears of living cheetahs differ markedly from those of all other felids alive today, with a greater overall volume of the vestibular system and longer anterior and posterior semicircular canals.

"This distinctive inner ear anatomy reflects enhanced sensitivity and more rapid responses to head motions, explaining the cheetah's extraordinary ability to maintain visual stability and to keep their gaze locked in on prey even during incredibly high-speed hunting," said coauthor John Flynn, the Frick Curator of Fossil Mammals in the Museum's Division of Paleontology.

These traits were not present in Acinonyx pardinensis, the extinct species examined by the researchers, emphasizing the recent evolution of the highly specialized inner ear of modern cheetah.

https://phys.org/news/2018-02-cheetahs- ... speed.html

Journal Reference:
Camille Grohé et al, Recent inner ear specialization for high-speed hunting in cheetahs, Scientific Reports (2018). DOI: 10.1038/s41598-018-20198-3

Abstract
The cheetah, Acinonyx jubatus, is the fastest living land mammal. Because of its specialized hunting strategy, this species evolved a series of specialized morphological and functional body features to increase its exceptional predatory performance during high-speed hunting. Using high-resolution X-ray computed micro-tomography (μCT), we provide the first analyses of the size and shape of the vestibular system of the inner ear in cats, an organ essential for maintaining body balance and adapting head posture and gaze direction during movement in most vertebrates. We demonstrate that the vestibular system of modern cheetahs is extremely different in shape and proportions relative to other cats analysed (12 modern and two fossil felid species), including a closely-related fossil cheetah species. These distinctive attributes (i.e., one of the greatest volumes of the vestibular system, dorsal extension of the anterior and posterior semicircular canals) correlate with a greater afferent sensitivity of the inner ear to head motions, facilitating postural and visual stability during high-speed prey pursuit and capture. These features are not present in the fossil cheetah A. pardinensis, that went extinct about 126,000 years ago, demonstrating that the unique and highly specialized inner ear of the sole living species of cheetah likely evolved extremely recently, possibly later than the middle Pleistocene.


Shape differences of the Vestibular System (VS, highlighted in blue) between the fossil and extant cheetah species. VS in lateral, anterolateral, and dorsal views from top to bottom. Black points = extinct Acinonyx pardinensis Procrustes coordinates; grey points = extant Acinonyx jubatus mean Procrustes coordinates. Numbers correspond to main regions of shape differences: 1, length of the common crus; 2, out-of-plane curvature of the lateral semicircular canal (SC); 3, shape of the anterior SC; 4, shape of the posterior SC; 5, angle between the anterior and posterior SC; 6, width of the lateral SC; 7, position of the bifurcation between the lateral and posterior SC.

https://www.nature.com/articles/s41598-018-20198-3.pdf
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Joined: February 11th, 2012, 7:29 am

April 11th, 2018, 11:01 am #38

How cheetahs outsmart lions and hyenas
Serengeti study shows that cheetahs use situation-dependent methods of protecting their hunted prey from larger predators


Date: April 10, 2018
Source: Springer


Two male cheetahs eat a kill.
Credit: Copyright Anne Hilborn

Cheetahs in the Serengeti National Park adopt different strategies while eating to deal with threats from top predators such as lions or hyenas. A new study in Springer's journal Behavioral Ecology and Sociobiology shows that male cheetahs and single females eat their prey as quickly as possible. Mothers with cubs, on the other hand, watch out for possible threats while their young are eating in order to give them enough time to eat their fill. The research was led by Anne Hilborn of Virginia Tech's College of Natural Resources and Environment in the US.

Cheetahs are medium-sized carnivores that live alongside large carnivores such as lions and spotted hyenas. These large carnivores are known to not only attack cheetah cubs, but also steal prey in an act called kleptoparasitism. Cheetahs do not have the strength to haul their kills up trees to keep them safe from scavengers as a leopard does, nor can they physically defend themselves against a lion. They therefore tend to hunt when larger predators are away or less active. Hilborn and her colleagues studied 35 years of observations from more than 400 hunts involving 159 cheetahs in the Serengeti in northern Tanzania to find out how cheetah behavior while eating is altered by threats from larger predators.

The researchers established that the tactics cheetahs use depend on which type of threat they face from large carnivores. The primary threat to male cheetahs and single females without cubs is having their kill stolen. They therefore spend little time watching out for attacks, and instead eat their prey as quickly as possible before it can be snatched away from them.

Mothers with cubs must first ensure the safety of their offspring and that they get enough to eat. Cubs can eat quite slowly because of the size of the cubs' mouths and their tendency to take regular breaks to rest or play.

"Instead of speed, mothers use vigilance to minimize risk," explains Hilborn. "They spend more time paused before eating, perhaps also to catch their breath, and are more vigilant. This increases the amount of time they spend eating, which in turn increases their overall handling time."

The research team believes that the behavior of a cheetah after a hunt depends on the territory it finds itself in. Cheetah mothers might, for instance, be less vigilant in the Kgalagadi Transfrontier Park in the Kalahari region of South Africa and Botswana, where lion densities are three times lower and spotted hyena numbers are 100 times lower than in the Serengeti.

Story Source: Springer. "How cheetahs outsmart lions and hyenas: Serengeti study shows that cheetahs use situation-dependent methods of protecting their hunted prey from larger predators." ScienceDaily. www.sciencedaily.com/releases/2018/04/180410103510.htm (accessed April 10, 2018).

Journal Reference:
Anne Hilborn, Nathalie Pettorelli, Tim Caro, Marcella J. Kelly, M. Karen Laurenson, Sarah M. Durant. Cheetahs modify their prey handling behavior depending on risks from top predators. Behavioral Ecology and Sociobiology, 2018; 72 (4) DOI: 10.1007/s00265-018-2481-y

Abstract
While handling large kills, mesocarnivores are particularly vulnerable to kleptoparasitism and predation from larger predators. We used 35 years of observational data on cheetah (Acinonyx jubatus) hunts in Serengeti National Park to investigate whether cheetahs’ prey handling behavior varied in response to threats from lions (Panthera leo) and spotted hyenas (Crocuta crocuta). Male cheetahs and single females, whose main threat was kleptoparasitism, minimized time on the kill by being less vigilant and eating quickly, thereby shortening their handling times. Mothers with cubs showed a different strategy that prioritized vigilance over speed of eating, which increased time spent handling prey. Vigilance allowed them to minimize the risk of their cubs being killed while giving cubs the time they need to eat at the carcass. Flexible behavioral strategies that minimize individual risk while handling prey likely allow mesocarnivores to coexist with numerous and widespread apex predators.

https://link.springer.com/article/10.10 ... 018-2481-y
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