Trends and biases in African large carnivore population assessments: Identifying priorities and opportunities from a systematic review of two decades of research

Peer-Reviewed Publication

PEERJ

 

IMAGE: LIONESS WALKING ON RE SAND-DUNE view more 

CREDIT: CHRIS STENGER

African large carnivores have undergone significant range and population declines over recent decades. Although conservation planning and the management of threatened species requires accurate assessments of population status and monitoring of trends, there is evidence that biodiversity monitoring may not be evenly distributed or occurring where most needed. 

 

New research published in the Open Access, peer-reviewed journal PeerJ provides the first systematic review of African large carnivore population assessments published over the last two decades (2000-2020), to investigate trends in research effort and identify knowledge gaps. The article is a timely review for a very important conservation topic, and provides an informed broad-scale framework for decision-making that is currently lacking in the field of large carnivore research in Africa - to guide funding, research investment, and priorities.

 

Researchers from the University of Oxford, the University of KwaZulu-Natal, Endangered Wildlife Trust, South Africa and Panthera used generalised linear models and generalised linear mixed models to identify taxonomic and geographical biases in previously published research into large carnivores in Africa, and also uncovered biases associated with land use type and author nationality.

 

“Research effort is significantly biassed towards lions (Panthera leo) and against striped hyena (Hyaena hyaena), despite the latter being the species with the widest continental range. African wild dogs (Lycaon pictus) also exhibited a negative bias in research attention, although this is partly explained by its relatively restricted distribution,” write the authors. “Our findings highlight the urgent need for additional cheetah population assessments, particularly in northern, western, and central Africa. Due to their large country ranges, studies in Chad and Ethiopia should especially be considered a priority.”

 

Population assessments have been biassed towards southern and eastern Africa, particularly South Africa and Kenya. Northern, western, and central Africa are generally under-represented. Most studies have been carried out in photographic tourism protected areas under government management, while non-protected and trophy hunting areas received less research attention. 

 

Outside South Africa, 41% of studies did not include authors from the study country, suggesting that significant opportunities exist for capacity building. Overall, large parts of Africa remain under-represented in the literature, and opportunities exist for further research on most species and in most countries.

 

The authors developed recommendations for actions aimed at overcoming the identified biases and provide researchers, practitioners, and policymakers with priorities to help inform future research and monitoring agendas.

 

Recommendations 

 

Reducing the identified geographical and taxonomic biases in population assessments would help ensure that all species and areas of conservation importance have an adequate knowledge base available, with the potential to improve their conservation outlook.

 

Geographical biases in research and assessments are immediate hurdles for science-based conservation management of African large carnivores. As a result, northern, western, and central Africa should be considered priority regions for future research.

 

Increased attention should in particular be given to the twenty-six countries which currently lack any published estimates, especially Angola, DRC, South Sudan, and Chad, given their considerable large carnivore country ranges and their potential importance for the conservation of these species. 

 

Building capacity of researchers and practitioners in large carnivore survey and monitoring techniques in under-represented areas should be a priority. The fact that only 59% of studies outside of South Africa included a co-author from the study country reinforces suggestions that research in developing countries is disproportionately led by scientists from more developed areas, and shows there is considerable need for such capacity building efforts. 

 

Donors and foreign researchers should maximise the involvement of local scientists, students, and practitioners in future assessments, including through capacity building initiatives such as the provision of training, funding, and equipment. Conservation donors and funders should encourage efforts in understudied regions, as well as for understudied species, to ensure that conservation research occurs where it is most needed. 

 

On a species level, population assessments of striped hyena are needed, and further population assessments of African wild dogs are essential, particularly given the species is classified as Endangered. Such efforts are especially required in countries that have been identified as critical for the species, but where no recent assessments have been carried out (e.g. Botswana and Tanzania). 

Urgent need for additional cheetah population assessments, particularly in northern, western, and central Africa. Due to their large country ranges, studies in Chad and Ethiopia should especially be considered a priority. As in the case of African wild dog, development and standardisation of cheetah population monitoring techniques, including the exploration of citizen-science based approaches, are recommended.

---

JOURNAL

PeerJ

DOI

10.7717/peerj.14354 

METHOD OF RESEARCH

Observational study

SUBJECT OF RESEARCH

Animals

ARTICLE TITLE

Trends and biases in African large carnivore population assessments: Identifying priorities and opportunities from a systematic review of two decades of research

ARTICLE PUBLICATION DATE

25-Nov-2022

HIERARCHY IS A PARASITE

Wolves emboldened by parasite more likely to lead pack: study

Story by AFP • 

Wolves infected with a common parasite are far more likely to become the leader of their pack, according to a new study, suggesting that the brain-dwelling intruder emboldens its host to take more risks.


Leader of the pack? A parasite may make grey wolves in Yellowstone National Park take more risks, research suggests© -

The single-celled parasite, Toxoplasma gondii, only sexually reproduces in cats but can infect all warm-blooded animals.

Between 30-50 percent of people worldwide are estimated to be infected with the parasite, which remains for life as dormant tissue cysts. However people with a healthy immune system rarely have any symptoms.

While some studies have reported an association between people having the parasite in their brain and increased risk-taking, other research has disputed these findings and no definitive link has been proven.

The new study, published in the journal Communications Biology on Thursday, took advantage of 26 years' worth of data on grey wolves living in the Yellowstone National Park in the United States to investigate how the parasite could affect their behaviour.

The researchers from the Yellowstone Wolf Project analysed the blood samples of nearly 230 wolves and 62 cougars -- the big cats are known spreaders of the parasite.

They found that infected wolves were more likely to foray deeper into cougar territory than uninfected wolves.

Infected wolves were also 11 times more likely to leave their pack than wolves without the parasite, the study said, indicating a higher rate of risk-taking.

And an infected wolf is up to 46 times more likely to become pack leader, the researchers estimated, adding that the role is normally won by more aggressive animals.

Study co-author Kira Cassidy told AFP that while "being bolder is not necessarily a bad thing," it can "lower survival for the most bold animals as they might make decisions that put them in danger more often."

"Wolves do not have the survival space to take too many more risks than they already do."

Cassidy said it was only the second study on T. gondii's effect on a wild animal, after research last year found increased boldness in infected hyena cubs made them more likely to get closer to -- and killed by -- lions in Kenya.

Laboratory research has also found that rodents with the parasite lose their instinctual fear of cats -- driving them into the hands of the only host where T. gondii can reproduce.

William Sullivan, a professor of pharmacology and toxicology at the Indiana University School of Medicine who has been studying T.gondii for more than 25 years, called the wolf paper "a rare gem".

However he warned that such an observational study could not show causation.

"A wolf that is a born risk-taker may simply be more likely to venture into cougar territory and contract Toxoplasma," he said.

But "if the findings are correct, they suggest we may be underestimating the impact Toxoplasma has on ecosystems around the world," he added.

- What about humans? -

"That's the million-dollar question," Sullivan said, adding that "no one knows for sure and the literature is mixed".

Ajai Vyas, a T. gondii expert at Singapore's Nanyang Technological University, warned against inferring that infection could increase risk-taking in people.

"There is a lot about human behaviour that is different from other animals," he told AFP.

People often get infected by T. gondii from eating undercooked meat -- or via their pet cat, particularly when cleaning out their litter boxes.

In some cases, especially in people with weakened immune systems, T. gondii can lead to toxoplasmosis, a disease that can cause brain and eye damage.

A Mind-Controlling Parasite Is Making Yellowstone Wolves Foolhardy

Story by Maddie Bender • The Daily Beast

Yesterday 

When a common parasite infects wolves, it changes their behavior and turns them into risk-taking animals that could help them become leaders of their pack—or get them killed. A new study published Thursday in the journal Communications Biology found that a wolf infected by Toxoplasma gondii, a single-celled parasite that invades warm-blooded animals, was over 46 times more likely to take over its pack’s leadership than an uninfected wolf, thanks to the parasite’s ability to induce more risk-taking behavior.


Photo Illustration by Kelly Caminero / The Daily Beast / Getty

“We focus so much on vertebrate dynamics—wolves and elk, and how they affect each other—and for a long time, it seems like we have generally ignored the fact that parasites might play a role in those relationships,” Connor Meyer, an ecology researcher at the University of Montana and the lead author of the new study, told The Daily Beast. “With something like Toxo, it seems like we should be giving parasites a little more credit.”

Host behavior modification—the buttoned-up, scientific way of saying “mind control”—is a common yet devious tactic that infectious diseases have evolved over time. Just look at “zombie ants,” which either describes ants infected with a fungus that takes over their brains; or a parasitic worm that causes ants to walk up blades of grass and lock their jaws, increasing the chance that a cow consumes them. Elsewhere in nature, parasitic worms can also zombify snails and cause their eye stalks to take on the appearance of maggots, which predacious birds find appealing.

Behavior modification that causes a host to be eaten by a predator usually means that the underlying parasite infects multiple host species as part of its full life cycle, and the same is true for Toxoplasma. The parasite can infect many different species, including humans—which is why pregnant women are advised to keep from scooping their cat’s litter. Some research suggests toxoplasmosis might modify our behavior by causing hormones like dopamine and testosterone to increase, but the only known host that allows it to sexually reproduce is the feline family that includes domestic cats—which means having a pet cat does raise the odds you might have Toxoplasma swimming around in your body. And once the parasite’s there, it might stick around for a lifetime, though people rarely display symptoms following the acute phase of infection.

But the spikes in dopamine and testosterone caused by Toxoplasma are especially important to pay attention to in other intermediate host species, since they can induce a phenomenon that scientists really call “fatal attraction.” Toxoplasma-infected animals like rats and hyenas become bolder around felines, increasing the odds that they’ll be eaten and the parasite can reproduce.

In other words, it would seem the parasite is trying to put its intermediate host in more dangerous positions where it's likely to be snatched up by a potential true host.

At Yellowstone National Park, it was a mystery how Toxoplasma was spreading to wolves, since they must ingest a form of the parasite called an oocyst, spread from a cat, to be infected. That is, until Meyer made the connection that a species of big cat roams the park: cougars. He and his co-authors believe that one aspect of wolves’ relationship to these cougars might look a lot like a dog’s household relationship to a cat.

“Some dogs really like raiding the litter box if you don’t get to it fast enough,” he said. “We would expect that wolves are very similar where when they come across cougar scat on the landscape, they very well might eat it and become infected that way.”

For the study, Meyer and his team tested blood samples from 62 different cougars and 229 wolves that lived in Yellowstone between 1995 and 2020. The highest proportions of infected wolves occurred in areas with high cougar overlap, in line with Meyer’s predictions.

Wolves’ infection statuses were also charted alongside their observed behavior, such as becoming leader of a pack or leaving the pack.

The team found that Toxoplasma-infected wolves were more likely to become leaders of their pack and on average left the pack earlier than uninfected wolves—an apparent contradiction that could be interpreted as the parasite increasing risk-taking and aggressive behaviors across the board, Meyer said.

But host behavior modification isn’t all bad. There’s a key advantage to the wolves of becoming pack leaders: “leaders become breeders” is the adage when it comes to the dominant male and female in a pack, Meyer said. Even though the wolves most likely cannot pass the parasite to their offspring, they may teach the pack to engage in riskier behaviors and spend more time near cougars, causing other members to pick up the infection.

Researching this wacky example of mind control may have lasting implications when it comes to monitoring the careful balance of Yellowstone’s ecosystem. The reintroduction of wolves to the park is “one of the greatest conservation success stories in North America,” Meyer said, and understanding infected wolves’ behavior can inform further conservation of the animals. A tiny parasite that can influence an entire ecosystem—now that’s proof that size doesn’t matter.

 

Translocation of SA cheetahs to India — ‘there is going to be a lot of heartache and pain’

Three cheetah cubs with their mother. Cheetah mothers have to be extra vigilant to protect their cubs as they are easy prey both for predators from above (raptors) and on the ground (lions). 

(Photo: Kalyan Varma)

By Don Pinnock
03 Oct 2022 0

Some say sending African cheetahs to India is a brilliant idea, others insist it’s possible but with warnings, and some say it’s an absolute disaster.

If the 20 African cheetahs destined for Kuno National Park in India die – and there’s a good chance they will – it won’t be met with the same fanfare as their arrival.

The question we would then need to ask is whether they were sacrificed for the greater good of conservation or for a national vanity project.


The cheetahs were planned to arrive on India’s Independence Day (15 August) but didn’t make the date. Instead, they got there on 17 September in time for the birthday of Prime Minister Narendra Modi, who released them into a boma in Kuno National Park.

Twelve more are about to arrive from South Africa, pending the signing of a memorandum of understanding.

Cheetah and cub. (Photo: Kalyan Varma)

Some say sending African cheetahs to India is a brilliant idea, others insist it’s possible but with warnings, and some say it’s an absolute disaster. The cost is estimated at R200-million in the first five years. The Wildlife Institute of India estimates that in the first year only 50% will survive.

Is it a reasonable project? You be the judge.

The Indian government

For India, the symbolism is important. Cheetahs have been integral to Indian heritage, folklore and culture since time immemorial. The last cheetah in India was shot in the 1940s. It’s the only large wild mammal to go locally extinct. Their return is a mark of national pride.

India’s environment minister, Bhupender Yadav, tweeted: “Completing 75 glorious years of Independence with restoring the fastest terrestrial flagship species, the cheetah, in India, will rekindle the ecological dynamics of the landscape.”

Their import also flags international cooperation around rewilding, the introduction of a top predator and the rebalancing of biodiversity.

After much legal wrangling, the introduction was approved by the Supreme Court of India in 2020. It was also approved by the Namibian government and is awaiting official approval from South Africa’s Department of Forestry, Fisheries and Environment.

What could possibly go wrong?

The vet

Cheetahs aren’t the best travellers. There’s a high risk of mortality in translocation. Seven of the first eight wild cheetah reintroductions attempted within South Africa between 1966 and 1995 failed, with the cats dying after release. More than 40 have died from immobilisation complications since 2011. Seven percent exported out of South Africa died this way. But we are getting better at it. The first eight arrived in India alive and well.

What about disease or predation in their new home? An assessment of the disease risk by Adrian Tordiffe, associate professor at the University of Pretoria, is reassuring. The chance of them either transmitting or contracting any communicable diseases, he said, was judged to be low. Non-disease risks, such as starvation or conflict with local predators such as leopards or striped hyenas, were also minimal.

But there is a problem: Kuno is unfenced. “We’re used to operating in South Africa with fenced reserves where you have quite a lot more control,” he said in an interview with Our Burning Planet. “In India, you have got a human population of 1.3 billion and no fences

.

Cheetah competition in India. (Image: Supplied)

“All the cheetahs released in India will be collared and satellite-monitored. In South Africa, if a cheetah decided to wander 100km beyond a park we’d use a helicopter to bring it back. But in Kuno they just have 4x4s.”

This means serial wanderers will have to be chased, drugged and returned. Cheetahs are known to be susceptible to capture stress and often die because of it. Serial escapees will be sent to Mukundra Hill Tiger Reserve, which is fenced. Despite its name, it’s free of tigers, but does have leopards, wolves and striped hyenas. It could see the first encounter between an African cheetah and a wolf.

Kuno has one of the highest leopard densities in the world. But hopefully, the cheetahs are predator-savvy. They come from Phinda in KwaZulu-Natal, where they have been exposed to lions, leopards and hyenas.

“Because they’re going into areas where there’s quite a high leopard density,” said Tordiffe, “we wanted animals that are really quite wild.

“They’re not naïve of those carnivores and they can avoid them, they can defend themselves against them, they’re really aware of what they are and the risks that they pose to them.”

But there are risks. In South Africa, leopards are responsible for 9% and lions 30% of relocated cheetah mortalities.

Visit Daily Maverick’s home page for more news, analysis and investigations

If all goes according to plan, the 20 cheetahs will stay in a fenced area at Kuno for a month or so before being released into the park. When the gates are opened, every cheetah is on its own.

The risks will not be just predators. Kuno is surrounded by farmers with cattle, sheep, goats, chickens and dogs. The young of cattle, sheep and goats could prove tasty, while dogs may be a vector for distemper and rabies. Though farmers are well compensated for loss to tigers and the same would apply for cheetahs, there is a bushmeat problem.

According to census research, Kuno has people who eat meat once a week or once a month on average. There is also a significant percentage that eats meat every day. Bushmeat snaring is prevalent in the region. People in the area were also found to own homemade guns, bows and arrows and catapults.

The facilitator

Vincent van der Merwe runs Cheetah Metapopulation and is both highly experienced in relocations and a consultant to the relocations from Namibia and South Africa. His job is to make sure they get there alive and well. The Namibian cheetahs arrived intact and he’s enthusiastic about the whole relocation plan.

“India has a completely different population methodology with a completely different mindset — they have a coexistence approach. There’s no fencing. There’s no retaliatory killings. Indians around Kuno belong to a completely different religious outlook.

“South Africa has a surplus of cheetahs and we would have to euthanise or contracept them, neither of which is optimal. So relocating is a good idea.

“There are definitely a lot of ambitious people involved enjoying the media attention,” he added, “but it’s also been a dream for many high-profile Indian conservationists. It’s gonna be one hell of an uphill battle, there are going to be massive losses initially.

“But, you know, we’ll learn. Indian parks have huge, unproductive buffer zones bringing in no revenue. They could hire them out as private game reserves.”

He says the successful establishment of cheetahs in the proposed introduction sites in India will need to be managed until at least 1,000 cheetahs are in place.

“This will require long-term commitment by South African and Namibian authorities to provide unrelated cheetahs for relocation to India. We hope that within 10 years we could have some form of population growth in India, but certainly, within the first 10 years of this project, there is going to be a lot of heartache and pain.”
The Indian conservationists

Once released, though, the big cats will almost certainly walk out of the unfenced park, “and then they’ll have a hell of a problem,” says Ullas Karanth, emeritus director for the non-profit Centre for Wildlife Studies and a specialist in large carnivores. “The cheetahs will get trashed and killed very quickly because there’s nothing outside of Kuno — it’s villages, dogs and farms.”

“There’s not any chance for free-ranging cheetah populations now,” adds Arjun Gopalaswamy, an independent conservation scientist who has conducted research on big cats in Africa and India. Cheetahs in India “perished for a reason”— human pressure, which has only got worse in the 70 years since the species disappeared. “So the first question is, why is this attempt even being made?”

Wildlife biologist and conservation scientist Dr Ravi Chellam of the Metastring Foundation says the cheetah project is poorly conceived and grossly expensive.

“The cheetahs will require intensive hands-on management over decades,” he said. “The government has still not implemented the 2013 court order to translocate Asiatic lions, of which there are only around 700 in the world, from Gir, Gujarat, to Kuno but they’re quick to implement a 2020 order to bring in cheetahs from Africa, which number around 7,000 in the world. Which is more endangered?

An Indian public awareness poster. (Image: Supplied)

“This project is being rushed through to meet some goals other than conservation. The conservation goals are unrealistic and even unfeasible. Unfortunately, this will be a very costly mistake. It will be one of the most expensive conservation projects India has undertaken.

“We do not have habitats of the size cheetahs require. Without suitable high-quality habitats, this project is unlikely to succeed.”

Prerna Singh Bindra, a wildlife conservationist and former member of the National Wildlife Board, also said she wouldn’t classify the cheetah translocation project as a conservation project.

“Such projects, though sexy, are a distraction to our core objective of conserving wildlife and ecosystems. The cheetah is one of the widest-ranging of big cats and is known to travel across areas in excess of 1,000 km2 in a year. Historically, India has lost about 90% to 95% of its grasslands, 31% in a decade between 2005 and 2015. So where will the cheetah roam if it were ever returned to the wild?”

As the South African Department of Forestry, Fisheries and Environment ponders over the memorandum of understanding it is about to sign, it’s hoped they’ll have looked at all sides of the question. DM/OBP

Cheetah reintroduction in India - Wikipedia

https://en.wikipedia.org/wiki/Cheetah_reintroduction_in_India
Cheetah reintroduction in India involves the attempt to introduce and sustain a small population of Southeast African cheetah in India more than 70 years after India

What does cheetah reintroduction mean for Kuno National Park?

TIMESOFINDIA.COM

TRAVEL NEWS, MADHYA PRADESH/

 Created : Sep 17, 2022

Synopsis

It was seven decades ago when this cat species was declared extinct in India. The Asiatic cheetah, more than 70 years ago, went extinct in India, mostly due to poaching. Now, in a very exciting turn of events, eight African cheetahs were brought to India today from Namibia as a part of Project Cheetah, the world’s first inter-continental large wild carnivore translocation project.

Read more: Cheetahs are back in India, a saga of world's fastest cats

Today, September 17, 2022, India celebrated Prime Minister Narendra Modi’s 72nd birthday, and the PM released the Namibian cheetahs into the Kuno National Park’s designated enclosure.

It wouldn’t be wrong to say that the whole country eagerly waited to welcome the African cheetahs, flown in on a special cargo flight for 10 hours from Namibia to Gwalior in Madhya Pradesh. From Gwalior, the eight cheetahs were flown by two Indian Air Force choppers to Palpur, near Kuno National Park.



As of now, the cheetahs are released into a quarantine enclosure at the park, which is now the new home to these eight feline newcomers. This reintroduction project is an effort to revitalise and diversify Indian wildlife and cheetah habitat.

The national park, first established in 1981 as a wildlife sanctuary, and later in 2018 as a national park, is a part of the Khathiar-Gir dry deciduous forests ecoregion. But one question comes to mind, why Kuno National Park for this reintroduction project?



Kuno’s geography consists of vast grasslands, open forest patches and hills, perfect for the big cats. Just like tigers have helped the forest ecosystem, we are hopeful that the cheetahs will help revitalise the open grassland ecosystem, which is facing the threat of extinction and also the improved protection of various species that are the cheetah’s natural prey. For this project, another 413 sq km was added to the national park.



The cheetahs, five females and three males, aged between 4 to 6 years of age, now share the park with Indian leopard, jungle cat, sloth bear, dhole, Indian wolf, golden jackal, striped hyena, Bengal fox. Their prey base includes ungulates like chital, Sambar deer, nilgai, four-horned antelope, chinkara, blackbuck and wild boar. One can’t deny the concerns about the well-being of the cheetahs in the wild where there are apex predators like the leopard and wolves. But one can only hope that nature will play itself out and the cheetahs will be able to thrive in Kuno. One can hope for this project to work.

Project Cheetah is also expected to boost ecotourism in the region. It goes without saying that now that the authorities have brought the cheetahs to their new home in India, they need to work towards protecting the wildlife from the main threat that once wiped the cheetah population off the face of India – humans. Can Kuno National Park have the same kind of attention and stricter rules as some of the major national parks in India?

FAQsWhere is Kuno National Park?

Kuno National Park is in Saran Aharwani in Madhya Pradesh

How many African cheetahs were brought to India?

What is Project Cheetah?

Cheetah Conservation Fund - CCF UK 

July 25  · Instagram  · 

Follow

You may have seen reports in the news that #cheetahs are being reintroduced to #india after being absent for 70 years! Here’s our Founder Dr Laurie Marker being interviewed by @aljazeeraenglish discussing how they went #extinct, and how the reintroduction will work.

Daytime pastoralist activities do not negatively affect spotted hyenas in Tanzania

by Forschungsverbund Berlin e.V. (FVB)

Spotted hyena with Maasai pastoralist and cattle in Ngorongoro Crater.

 Credit: Oliver Höner/Leibniz-IZW

Pastoralists herding their livestock through the territories of spotted hyena clans along dedicated paths during daytime do not reduce the reproductive performance of hyena clans, nor elevate the physiological "stress" of spotted hyenas. This is the result of a new study led by scientists from the Leibniz Institute for Zoo and Wildlife Research (Leibniz-IZW) and the Ngorongoro Conservation Area Authority (NCAA).

The scientists analyzed 24 years of demographic and physiological data from eight spotted hyena clans—two of which were exposed to activities by pastoralists. The activities of pastoralists were predictable, diurnal and did not disrupt important behaviors in the mostly nocturnal hyenas. This may have allowed the population to perform well, the scientists suggest. The open access paper is published in the Journal of Animal Ecology.

Human activities can strongly affect wildlife but the effects can vary greatly, depending on the type of activity and the characteristics of the wildlife species involved. To promote human-wildlife coexistence, it is therefore important to assess which activities are sustainable for a given species.

Most past research has documented major changes in the behavioral response of such species to human activities, but did not examine whether such changes are indicative of the Darwinian fitness of wildlife (in terms of its survival and reproductive success) or physiological effects such as "stress" or allostatic load, which are much more relevant to conservation.

"Acquiring the long-term data for such research—especially on large, group-living carnivores, which may be particularly conflict-prone—is not easy because of the enormous financial and temporal demands involved. We assessed for the first time the Darwinian fitness and the physiological effects of a common human activity—livestock herding—in light of the biology and social system of our wildlife species," explains first author Arjun Dheer, doctoral student at the Leibniz-IZW.

The investigation was conducted on eight clans of spotted hyenas (Crocuta crocuta) living in the Ngorongoro Crater, a UNESCO World Heritage Site in northern Tanzania. "Livestock grazing and using mineral licks occurred predictably on a near-daily basis within the territories of two of our eight study clans between 1996 and 2016," adds Dheer.

This created a natural experiment of exposed and unexposed clans which the scientists exploited. "We tested whether the hyenas of the exposed clans had fewer surviving offspring than the unexposed hyenas and whether the herding activities increased the physiological 'stress' of the hyenas," explains Dr. Oliver Höner (Leibniz-IZW), head of the Ngorongoro Hyena Project and senior author of the paper.

To assess the fitness effects, the scientists used 24 years of detailed demographic data from the eight clans and to estimate physiological stress, they measured the concentration of glucocorticoid metabolites (fGMC) in 975 feces from 475 hyenas. The team also accounted for the effects of additional ecological parameters such as disease outbreaks and the abundance of African lions (Panthera leo), the hyenas' main competitor, and prey.

The main result was that hyena clans exposed to Maasai pastoralists moving through their territory with their livestock had similar juvenile recruitment and fGMC levels as unexposed clans. "Our results suggest that the hyenas in the Ngorongoro Crater coped well with daytime pastoralism," explains Dheer. A likely explanation for the lack of detectable effect on hyenas is that the activity was predictable and minimally disruptive because it occurred during daytime.

"Hyenas are mostly nocturnal when it comes to critical behaviors such as hunting," explains Höner. Even if pastoralist activities forced other critical hyena behaviors such as the nursing of young cubs into nighttime, it might not have been too much of an adjustment for them to make. "Spotted hyenas are behaviourally flexible. In other areas, they were observed to move their cubs to dens further away from the paths that pastoralists used, or to nurse more at night," Höner says.

The authors caution that such results should not be extrapolated in uncritical fashion. "In areas where pastoralism is more intense and environmental conditions such as the abundance of wild prey are less favorable than in the Ngorongoro Crater, pastoralist activities may well have a significant detrimental effect even on a behaviorally highly flexible species such as the spotted hyena," explains Höner.

"Our investigation highlights the need to develop evidence-based coexistence strategies within a local context to benefit both stakeholders and wildlife. It also underscores the importance of interpreting the effects of human activity in light of the socio-ecology of the species of conservation interest," concludes Victoria Shayo (Head, Department of Wildlife and Rangeland Management, Ngorongoro Conservation Area Authority). Additional scientific analyses that cover a variety of anthropogenic activities and species—and that measure effects on fitness and physiology—will be conducive to promoting human-wildlife coexistence.Emotions and culture are most important for acceptance of carnivore management strategies

More information: Arjun Dheer et al, Diurnal pastoralism does not reduce juvenile recruitment nor elevate allostatic load in spotted hyenas, Journal of Animal Ecology (2022). DOI: 10.1111/1365-2656.13812

Journal information: Journal of Animal Ecology 

Provided by Forschungsverbund Berlin e.V. (FVB) 

Caller ID: Hyena ‘whoops’ feature individual signatures

Study also finds repetition of whoops may improve identification

Peer-Reviewed Publication

UNIVERSITY OF NEBRASKA-LINCOLN

 

IMAGE: A STUDY HAS REVEALED THAT LONG-DISTANCE HYENA CALLS FEATURE SIGNATURES UNIQUE TO INDIVIDUALS — A FORM OF CALLER ID DISTINCT ENOUGH THAT HYENAS CAN LIKELY TELL ONE FROM ANOTHER. view more 

CREDIT: ELI STRAUSS

As dusk begins cloaking the Maasai Mara grasslands of southwestern Kenya, a spotted hyena slinks beneath the woody umbrella that is the acacia tree.

The carnivore pauses, its rounded ears cocking forward as a faint sound sails in, an airborne missive traversing three miles at 767 miles per hour. Again, then again. Whhhhhooo-OOOppp! There it is… the call of a fellow spotted hyena, repeated rapidly enough to warrant attention. A warning of lions in the area, maybe, or of one hyena clan encroaching on another’s territory.

To help or not to help? With so much ground to cover, and so much potential peril lying beyond it, the answer could depend on who, exactly, is on the other end of the long-distance call. For spotted hyenas, then, identification is no laughing matter. But it is a whooping one, says a new study from the University of Nebraska–Lincoln’s Kenna Lehmann and colleagues.

By applying machine learning to audio clips collected from the field, the team has concluded that hyena whoops feature signatures unique to individuals — a form of caller ID distinct enough that hyenas can likely tell one from another. For the first time, the researchers also managed to quantify how much repeating a call, as spotted hyenas do, might improve the odds of being identified.

The fact that spotted hyena clans are built on hierarchies of social rank, yet consist of multiple families that regularly come together and disperse across the savanna, makes individual identity especially important.

“Hyenas don’t treat every individual in the clan the same, so if they’re deciding whether to show up and help someone, they want to know who they’re showing up to help,” said Lehmann, a postdoctoral researcher at Nebraska.

In its search for vocal signatures, the team turned to what’s known as a random forest model. The researchers first trained the model by feeding it the identities of each hyena they had recorded, along with a massive number of acoustic traits extracted from each of its whoops.

From there, the model used a randomly selected series, or bout, of whoops from one hyena to generate decision trees. Each branch of a tree represented a binary choice in an acoustic trait from a batch that was also randomly selected. The model might begin by splitting the hyena whoops by higher vs. lower frequencies, for instance, then further divide those groupings into, say, longer vs. shorter calls, and so on. Ultimately, the tip of every branch represented a vote in favor of a particular hyena.

After assembling 500 of those haphazard decision trees — a random forest — the model predicted a given whoop’s identity based on which hyena received the most votes from those 500 trees. The team put its trained model to the test by asking it to identify which one of 13 hyenas produced a randomly selected bout of whoops, then repeated that test 999 times.

The model correctly paired a whoop bout with its hyena roughly 54% of the time, or about six times more often than would be expected by chance. That success rate suggests there’s enough variation in the whoops of different hyenas, and enough consistency within the whoops of a single hyena, for the model to reasonably tell them apart. And if the model can discern those differences, Lehmann said, it’s reasonable to presume that the hyenas can, too.

Three traits of the whoops seemed especially instructive: the duration of a call, the highest frequency of the call, and the average frequency during the portion of the call that was most consistent in pitch. The greater the disparity in those traits, the more likely the model — and potentially, hyenas themselves — would be to distinguish among the sources of the respective whoops.

Still, 54% is well short of 100%, even before accounting for the challenges inherent to communicating with a fellow hyena in the Maasai Mara. For one, spotted hyena clans can swell to more than 125 members, a number to seemingly strain even the most voluminous, airtight memories. There’s also the possibility of acoustic nuances getting lost in transmission, particularly when those signals are traveling multiple miles before reaching rounded ears. Wind, rain and other animal calls, meanwhile, can introduce noise to the signal.

“There’s an understanding that one of the ways to get your message across is to repeat it,” Lehmann said, “especially if you’re in a noisy environment or if you’re communicating over long distances.”

Prior research has shown that penguins, for example, reiterate their calls more often when the wind picks up. And other studies have found evidence that various animal species favor repetition under similarly noisy circumstances. But as far as Lehmann and her colleagues could tell, none had quantified the extent to which repeating an animal call might actually improve the transmission of information.

So the team again resorted to its random forest model. When the model guessed the identity of a hyena on the basis of just one whoop, it correctly pegged that identity only about half as often as it did when provided with three whoops. That accuracy rose even further with additional calls, peaking at seven whoops.

“It’s like getting a little bit more information (each time),” said Lehmann, who previously studied vocalizations in orcas. “The first time you hear it, you might notice: Oh, that was definitely a male or a female voice. Then, the next whoop, you might be able to narrow it down further.”

Lehmann and her colleagues knew that the calls of some animal species also contain signatures that differentiate the groups to which they belong from other same-species groups they might come across — somewhat akin to human accents or dialects. She recalled that some researchers studying orcas had become so familiar with pod signatures that the researchers could instinctively tell them apart. (One researcher claimed that a certain pod’s calls were “more nasally” than others’.)

Given the size of spotted hyena clans, Lehmann figured that their whoops, too, might employ a group-specific signature.

“Obviously, if you just have to remember what your group sounds like, and you don’t have to remember each of the 100-plus individual voices, that would be a lot easier to do,” she said.

When the researchers went looking for a group signature in the random forest, though, they couldn’t find one. One potential explanation: The apparent ability to memorize so many individual signatures may have rendered a clan signature either useless or, at best, not useful enough to bother developing.

“If you know who the individual is, you know what group they’re in,” Lehmann said. “Animals are pretty good at associating that information.

“So if they need individual signatures for other reasons, then there just may have never been a need to also develop a group signature, which is what this finding suggests. They should be able to keep track of all the individual voices and be able to distinguish: If this is Individual X, they’re in my group. I can choose to help them based on them being a group member, but maybe there are more decisions to be made about whether they’re a group mate that I actually want to help.”

‘A million different stars that have to align’

All of the team’s findings — the presence of individual signatures, the absence of a clan signature, the utility of repetition — ultimately originated not from a random forest but from the savanna of Kenya’s Maasai Mara National Reserve. There, Michigan State University’s Kay Holekamp and colleagues have been conducting research on the spotted hyena since the late 1980s.

Lehmann herself spent a year in the Maasai Mara, which takes its name from the Maasai people who have long inhabited it. From 2014 to 2015, the then-doctoral student and several colleagues regularly drove west from Kenya’s capital, Nairobi, to a field site at the reserve.

“The first time I went out there … I thought, ‘Oh, I’m gonna be sleeping on the ground for 10 months, in a sleeping bag,’” said Lehmann, who soon learned that a sizable canvas tent and a soft bed awaited her. “But we were pretty spoiled out there, to be perfectly honest.”

If the accommodations were cushier than expected, the data collection proved anything but. From their vantage point in a Toyota Land Cruiser, Lehmann and her colleagues would point a directional microphone out the window and flip on an audio recorder. Unfortunately, the team was very much subject to the vagaries of Murphy’s law.

“You need to not be driving. And the car has to be turned off,” she said, noting that its engine drowned out the sounds of the Maasai Mara. “And the hyena has to whoop. And you have to be able to actually … see who it is. They can’t be in a bush. And they have to be close enough so that you can get a good recording. And the other hyenas need to be quiet at the same time. There are just, like, a million different stars that have to align to get a good recording that you can then use in an analysis like this.”

Under those circumstances, Lehmann said, patience was more than a virtue. It was a necessity.

“With this handheld recording equipment, we were opportunistically, constantly recording and just hoping that they whooped for us,” she said, laughing.

Over those months of hoping and waiting, the researchers stayed busy observing and chronicling behaviors that would inform other studies. As they did, they caught glimpses of the individuality that their analyses of the hyenas’ whoops would, years later, come to affirm.

“You definitely get to know that different individuals have different personalities or might react a certain way in different situations,” Lehmann said. “So it’s always fun to just get to know the hyenas and their little interactions and the dramas that might be going on in their lives.”

The team reported its findings in the journal Proceedings of the Royal Society B. Lehmann and Holekamp authored the study with Ariana Strandburg-Peshkin of the Max Planck Institute of Animal Behavior, Frants Jensen of the Woods Hole Oceanographic Institution, and Andrew Gersick of Princeton University. The researchers received support in part from the National Science Foundation.

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JOURNAL

Proceedings of the Royal Society B Biological Sciences

DOI

10.1098/rspb.2022.0548