We all know that human activity can influence the lives of nearby animals, especially those top predators that now have to play second fiddle to our ever-expanding interests. However, a new study has shown that not only do our actions impact them, but also our mere presence may cause majestic killers like pumas to grow so fearful that they change their hunting habits for the worse.
In the first-ever real-time tracking of leopard populations in India, researchers have determined that the big cats are surprisingly fearless when it comes to wandering near human neighborhoods. This was determined in a new GPS study, which has uncovered how these animals try to thrive in a man’s world.
That’s at least according to a new and fascinating study recently published in the Journal Proceedings of the Royal Society B, which details how, among pumas living in California, those living closest to humans were found to kill a lot more prey, but eat less of each kill, compared to pumas in more wild and secluded areas.
This was determined after a team of scientists from the University of California captured and tagged 30 wild pumas with GPS collars so they could track their movements. The territory and hunting grounds of these animals were then identified, breaking the pumas up into those that are living either near more rural or suburban human environments. The team also investigated kills, measuring just how much of each kill was eaten before a puma elected to slip away.
What they found was startling. In areas near a higher density of human housing, female pumas in particular were found to kill about 36 percent more large prey – mainly deer – than the more “rural” pumas.
Strangely, it wasn’t that the suburban pumas were hungrier. Instead, it appears that they are eating less of each kill – revisiting kill sites less frequently and spending less time taking their meals, compared to your average puma.
It is a rule in ecology that big animals outcompete little animals. Sometimes the big animals kill the little animals, sometimes the big animals eat the little animals, and sometimes the big animals drive the little animals out of one territory and into another, safer one. That basic pattern – “interspecific competitive killing” – has pushed scientists to try to understand how large carnivores shape entire ecosystems. Continue reading →
The astonishing spectacle of a leopard savaging a crocodile has been captured for the first time on camera. A series of incredible pictures taken at a South African game reserve document the first known time that a leopard has taken on and defeated one of the fearsome reptiles. The photographs were taken by Hal Brindley, a wildlife photographer, who was supposed to be taking pictures of hippos from his car in the Kruger National Park.
The giant cat raced out of cover provided by scrub and bushes to surprise the crocodile, which was swimming nearby. A terrible and bloody struggle ensued. Eventually, onlookers were amazed to see the leopard drag the crocodile from the water as the reptile fought back. With the crocodile snapping its powerful jaws furiously, the two animals somersaulted and grappled. Despite the crocodile’s huge weight and strength, the leopard had the upper hand catching its prey by the throat. Eventually the big cat was able to sit on top of the reptile and suffocate it. In the past, there have been reports of crocodiles killing leopards, but this is believed to the first time that the reverse scenario has been observed.
Mr Brindley said: ‘I asked many rangers in South Africa if they had ever heard of anything like this and they all said NO. ‘It just doesn’t make sense. The meat you get out of a crocodile is just not worth the risk it takes a predator to acquire. The whole scene happened in the course of about 5 minutes. Then the leopard was gone.
The wolves’ return to Yellowstone and the subsequent recovery of plants that elk had been eating to death in their absence has become one the most popularized and beloved ecological tales. By the 1920s humans had misguidedly wiped out most of the wolves in North America, thinking that the only good wolf was a dead one. Without wolves preying on them, elk and deer (also calledungulates) exploded in number. Burgeoning ungulate populations ravaged plant communities, including aspen forests. Decades later, the wolves we reintroduced in Yellowstone hit the ground running, rapidly sending their ecological effects rippling throughout the region, restoring this ecosystem from top to bottom. Yet today some scientists caution that this story is more myth than fact because nature isn’t so simple.
For decades scientists have been investigating the ecological role of wolves. In his 1940s game surveys, Aldo Leopold found ungulates wiping out vegetation wherever wolves had been removed. He concluded that by controlling ungulates, wolves could restore plant communities and create healthier habitat for other species, such as birds.
Since Leopold’s time, many scientists have studied food web relationships between top predators and their prey—called trophic cascades. In the 1960s and 1970s Robert Paine, working with sea stars, and James Estes, working with sea otters, showed that ecosystems without top predators begin to unravel. John Terborgh called the ensuing rampant species extinctions an “ecological meltdown.” Paine created the metaphorical termkeystone species to refer to top predators and noted that when you remove the keystone, arches and ecosystems collapse. Over the years ecologists found trophic cascades—also called top-down effects—ubiquitous from coral reefs to prairies to polar regions. However, William Murdoch and others have maintained that sunlight and moisture, which make plants grow, drive ecosystem processes from the bottom-up, making predators relatively unimportant. The Yellowstone wolf reintroduction provided the perfect setting to test these contrasting perspectives.
In the mid-1800s in his book The Origin of Species, Charles Darwin presciently described nature as a “tangled bank.” Nature’s complexity results from myriad species and their relationships with other species and all the things that can possibly affect them individually and collectively, such as disease, disturbance, and competition for food. Science works incrementally, taking us ever deeper into nature’s tangled bank as we investigate ecological questions. Each study answers some questions and begets new ones. Sometimes we find contradictory results. Learning how nature works requires what Leopold called “deep-digging research” in which we keep searching for answers amid the clues nature gives us, such as the bitten-off stem of an aspen next to a stream where there are no wolves.
Trophic cascades science that focuses on wolf effects is still in its infancy, with huge knowledge gaps. For example, we’ve linked wolves to strong effects that cascade down through multiple food web levels. However, we’re just starting to parse how context can influence these effects. Some Yellowstone studies have found that wolves have powerful indirect effects on the plants that elk eat, such as aspens, due to fear of predation. With wolves around, elk have to keep moving to stay alive, which reduces browsing pressure. Conversely, a growing body of studies are finding no wolf effect—that aspens in places with wolves aren’t growing differently than those where predation risk is low. Other studies have found that wolf predation risk doesn’t affect elk feeding behavior. In my own research I’ve found that wolves need another keystone force—fire—to most effectively drive trophic cascades. With wolves and fire present, elk herbivory drops, aspens thrive, and biodiversity soars due to the healthy habitat created by young, vigorously growing aspen.
It’s human nature to try to find simple solutions. Today we are grappling with monumental environmental problems such as climate change and habitat fragmentation. Due to the wolf’s iconic status and our need to fix broken ecosystems, the environmental community and the media have run with the science that shows a strong wolf effect. This has inspired other scientists to prove that ecosystems are more complex than that. These dissenting studies demonstrate that the wolf dwells in a tangled bank, working alongside many other ecological forces.
Tangled banks seldom yield simple answers. However, arguing about what exactly carnivores do ecologically and why we need them is fiddling while Rome burns. Large, meat-eating animals improve the health of plant communities and provide food subsidies for the many species that scavenge on their kills. A system with wolves in it is far richer than one without and can support many more grizzly bears, coyotes, wolverines, and eagles. There are things we don’t know and disagreements about what we do know. But given the accelerated human-caused extinctions we are experiencing today, a precautionary approach to creating healthier ecosystems means conserving large carnivores.
Beyond empiricism, scientists often operate based on instinct. Instinct led Darwin to dig more deeply into species adaptation and Leopold to doggedly delve into the effects of predator removal. For many of us who conduct trophic cascades science, our instincts are telling us that wolves should be conserved in as high a number in as many places as possible, due to the invaluable benefits they can bring to ecosystems. To do anything other than conserve wolves would be foolish, given all we’ve learned thus far.
It was late in the summer, and the two young lions had been on a camel killing spree. Over a period of three months, they had entered the villages of the Samburu people at night and killed ten prized camels.
It wasn’t long before they paid the price. One hot, hazy day in early September, when the male lions were napping under a scraggly acacia tree, a group of five young men came upon them. The men fired their AK-47s. Lguret, whose name means “cowardly,” ran off. Loirish, who was the more aggressive of the pair, may have stood his ground. He may even have tried to fight back, but he was no match for the rifles.
Samburu warrior Letoiye mourns the loss of Loirish, a lion he had been tracking.
Then the men butchered Loirish. They used their knives, adorned in colorful plastic as all Samburu warrior knives are, to cut off the lion’s head and feet. Then they took Loirish’s head and burned it in a small fire, an unusual act that was probably meant to destroy the GPS tracking collar we had placed on him to track his movements so we could warn herders. By the time we got to the grisly site, Liorish’s feet were missing. The men had taken them, perhaps to be sold on the growing black market for traditional Chinese medicine.
Letoiye, a member of the Samburu tribe and a part of our field team which had been tracking Loirish up to that day, stared at the blackened head in the pit and asked no one in particular, “Why did they kill my lion?”
Liorish unfortunately shares his fate with a growing number of large carnivores around the world who have clashed with humans and didn’t survive. Of the 31 large carnivores species like him—including lions, tigers, cougars, wolves, and snow leopards—most live not in some pristine wilderness, as we’d like to believe, but in landscapes dominated by humans and their activities. As a result, these animals are caught in a struggle between two sides of humanity—the one that wants large carnivores preserved and the other that would like to see them eliminated.
Letoiye is a Samburu moran, or warrior, a group that has traditionally been neglected in conservation. He never went to school and instead roamed the countryside tending to his family’s livestock while keeping a watchful eye on the land around the village. Despite their lack of formal education, Letoiye and his fellow moran possess skills that are the envy of many biologists and wildlife authorities. Because their job is to ensure their community’s security—which in rural East Africa often involves watching for predators—the moran know an impressive amount about lions and other predators.
A lioness gazes over the plain at Buffalo Springs National Reserve in Kenya.
Warriors like Letioye inspired us to set up Warrior Watch four years ago. They offer an intimate knowledge of the landscape and how lions and other wildlife move throughout it. In return, we teach Letioye and his peers how to identify each lion’s unique whisker spot pattern and how to discuss carnivore issues with fellow Samburu. We also offer weekly lessons on reading and writing in English and Kiswahili.
Before Warrior Watch, it wasn’t uncommon for moran to hunt and kill lions without question from their peers. But now, this program and others in Kenya are proving that attitudes towards lions and other large carnivores can change. A recent study of the program showed that participating warriors and their communities had a higher tolerance of lions and better understanding of their value.
The situation in the United States is not much different from the Samburu in Kenya. In California in 2013, for example, the state’s Department of Fish and Game issued 148 permits to eliminate cougars that had killed livestock and pets. As the suburbs expand out into once-wild areas, cougars are becoming more common in people’s backyards, where they occasionally kill goats and pets. While our livelihoods don’t always depend on our animals in the same way that the Samburus’ rely on their livestock, cougar-human clashes in California illustrate a broader point. The U.S. and Kenya share a bond that is at the heart of human-carnivore conflict: we both kill carnivores when we perceive them as threats to things we value.
Population at Risk
The reality is, of course, that we are a far greater threat to carnivores than they are to us. The cougar, for example, was all but eliminated from the eastern half of the United States during the 20th century. And in Africa, in the last half a century, the number of lions roaming in the wild has declined from 200,000 to fewer than 35,000. That’s mostly due to habitat destruction by humans. Lions used to roam most of the continent. Today, they occupy just 20% of their original territory, scattered across the continent and separated by cities, highways, villages, and farm fields. Some live on reserves, but that protected area isn’t enough to cover lions’ still expansive home ranges.
A moran scouts the savannah
A large number of conservationists favor creating more protected areas like national parks and reserves. After all, the largest intact populations of lions live in Selous and Ruaha National Parks, giant expanses of land under protection in Tanzania. These parks not only protect lions, they also support the entire ecosystem, fostering healthy savannahs that nurture gazelles and other prey species that keep lions sated. They also generate income through tourism, a not unimportant fact in many impoverished regions.
But protected areas haven’t been a panacea for large carnivores. As in the U.S., most African parks do not offer complete protection. Poachers have infiltrated many parks specifically to go after lions, while herders grazing their livestock inside park boundaries inadvertently take resources away from lion prey like gazelles and wildebeest.
Which is why some conservation biologists are suggesting that the only way to truly protect lions is to fully enclose reserves in fences. Yes, this would trap lions inside the parks, but it would also create a physical barrier between them and us. Such a move certainly has the potential to reduce poaching and limit human-animal conflict, but it could also reduce the viability of individual lion populations inside. Large carnivores like lions require expansive ranges to meet their daily needs. Plus, they can suffer from a phenomenon known as bottlenecking when overcrowded, which can lead to higher incidence of genetic disease and inbreeding. Fencing in lions to creating carnivore islands is one tool that might be effective in some cases, but given the potential for problems, it is not a “one size fits all” solution.
A better solution is to raise the tolerance of the land—and the people—living around protected areas. Lions, cougars, and other large carnivores will be able to live with people if they have safe refuge and as long as we keep ourselves and our property at a safe distance. Yet carnivores don’t belong in every human landscape, so we also need to carefully manage the areas where they can be supported.
That’s why we’re working hard in northern Kenya to create these landscape mosaics where local people can tolerate carnivores. We use a combination of high-tech research activities combined with low-cost community-sourced education programs like Warrior Watch. This year, we are fitting GPS-enabled tracking collars on ten young adult male lions. By mapping lion movements through the landscape, we can identify key corridors and refuges that might be prioritized for lions. The tracks also let us know which communities are in the lions’ territories so we can reach out to them with programs like Warrior Watch.
One of the lions collared and tracked as a part of the Warrior Watch program
At the same time, we’re also using the GPS collars to tell herders where the predator hot zones are. That way they can keep their livestock clear, avoiding unnecessary confrontations and losses. We can also track lions like Loirish that are known for killing livestock. When we locate one, our warriors go in to tell the villagers to be especially vigilant.
We can apply these lessons here in the U.S., too. As cougar and other carnivore populations make a comeback, a mixed approach is key. Protected areas are certainly important, since they provide carnivores and their prey with crucial strongholds. But we also need people to develop a tolerance to carnivores if we are to sustain that coexistence.
It’s starting to happen in places like the Santa Cruz mountains where conservation groups, state agencies, academic institutions, and landowners are working together to improve tolerance of cougars. Homeowners are learning how to properly fence their goats to keep them safe from cougar attacks, which can reduce the need to kill cougars in retaliation. And local governments are installing culverts under roadways to let cougars cross highways without risking dangerous collisions with vehicles. There are other innovative measures, too, like the protection of a forest behind a cement plant that cougars took a liking to. Portions of the plant grounds are open for recreational hiking while the important cougar habitat is being left intact. There’s something for everyone.
Additionally, we need programs that educate hikers and pet owners as well as ones to work with groups, like the Samburu warriors, that haven’t been a part of traditional outreach programs.
Finally, the most important thing to remember is that everyone’s point of view needs to be included in the process. It’s useful to keep in mind that the Samburu don’t need to be told how to live with lions—they’ve been doing that for tens of thousands of years—or that Americans don’t like being pandered to. Together, we can figure out how humans, livestock, pets, and wild carnivores can live together in increasingly crowded landscapes.
Back in Kenya, Letoiye remains troubled by the killing of Loirish. In some respects, his new way of thinking clashes with the old ways that many of his people still follow. He no longer sees lions as a threat, but as a unique part of his identity. He feels a responsibility to protect them, and he works everyday to convey a message of coexistence. But not everyone wants to listen. Loirish’s death is perhaps the most vivid reminder of that.
Fortunately, Letoiye’s not alone. Another warrior on our team, Jeneria, once said something that gives me hope: “Lions are in my blood now.” Losing lions is something Letoiye, Jeneria, and their fellow warriors are no longer willing to accept.
With only in the region of 120 free roaming desert adapted lion remaining in Namibia, and the increase in incidents of human-animal conflict on the rise, Dr Philip Stander of Desert Lion Conservation, tracks and monitors these unique animals.
Relying solely on donations from the public and support from local tourism operators, Dr Stander has devoted his life’s work and resources to researching the desert adapted lions of Namibia, managing human-animal conflict in an environment of sustainable tourism.
Over the past few months conflict between the lions and farmers in the Kunene region of Namibia has reached a peak. Money is urgently needed for the erection of kraals and more collars, so that lions can be tracked in real-time and farmers alerted as to their position. Dr Stander relies solely on donations from the public and support from local tourism operators,these can be made by contacting firstname.lastname@example.org