Big Cats’ Big Problem

Big Cats’ Big Problem

By using new technology, Dr. Stuart Pimm has realized that lion and cheetah habitats are disappearing in Africa. With the help of his students and some National Geographic grantees, Dr. Pimm is using innovative ideas to ensure that Africa's big cats don't vanish.


6 - 12+


Anthropology, Biology, Ecology, Social Studies, Economics

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During the summer of 2010, Dr. Stuart Pimm traveled to the remote Tete Province in Mozambique to see if the region could become a wildlife corridor, connecting the lion populations of Mozambique with the lion populations of Zambia.

Upon arriving, he discovered that the land had been cleared for crops.

For Pimm, a member of the committee for National Geographic’s Big Cats Initiative, the discovery was a revelation. The Big Cats Initiative is a project aimed at halting the decline of big cats in the world. Pimm teaches conservation ecology at Duke University in Durham, North Carolina, and his students are directly involved in the big cats research.

Pimm is attempting to identify dwindling lion and cheetah habitats in Africa. After the trip to Mozambique, he began to realize that satellite images didn’t accurately depict what was happening over a lot of Africa. (The images came from Landsat, a series of satellite expeditions observing the Earth.)

Pimm and a team of his students are finding that areas that used to be thought of as prime big cat habitat are being rapidly converted to cropland by Africa’s human population. Pimm’s group uses new technology, including Google Earth, to zoom in on Africa’s savannas.

“We, my students and I, have produced maps of Africa that are really quite alarmingly different to what other people have produced in the past,” Pimm says. “What we are finding is that across a large area of Africa, the savannas have been converted to small fields, to small areas of crops. It’s hard to see that on [satellite imagery from] Landsat, but with all the imagery that we have that’s made available now by Google Earth, we can begin to see an enormous amount more detail.”

Pimm believes the decreasing wildlife habitat is a result of the human and lion populations vying to settle in the same environment.

“The problem is that lions are sort of like Goldilocks,” Pimm says. “They don’t want it too wet, and they don’t want it too dry. They want it just right. We humans are like Goldilocks too. We don’t want the places that are too wet or too dry, so we tend to be using the same places in Africa. If there are too many of us, then there can’t be any lions.”

Reinforcing Bomas

Mapping the habitat for lions and cheetahs within Africa is only one aspect of Pimm’s work for the Big Cats Initiative. He also travels to the continent to meet with scientists and conservationists who are funded by the program. Most of these grant recipients are attempting to reverse the decline of lion and cheetah populations.

Anne Kent Taylor, for instance, is working to reinforce bomas. Bomas are traditional livestock enclosures, usually made from thorny bushes. Lions are often able to break through bomas and attack the cattle inside. This causes the local human population to retaliate by killing the lions.

Taylor realized that if the lions are unable to penetrate the bomas and dine on the cattle, the human population is more tolerant of the predators. Taylor and her team of conservationists have been reinforcing bomas with chain-link fences. The metal fences are much more resistant to lion attacks.

Pimm supports Taylor’s work.

“With lions sort of running into these bomas quite regularly and getting killed in retaliation, I think this project is going to have immediate consequences in reducing the number of lions killed,” he says.

Another aspect of Pimm’s work is looking at the range of African lions. The lions, Pimm argues, need more land to patrol than is offered by the vast series of preserved land throughout the continent.

“The national parks in Africa, even though they are big, are not always big enough for the lions,” Pimm says. “Lions take up an enormous amount of space. They eat meat. They need an enormous amount of food. So unless you have enough room for them, you are not going to have viable populations.”

Parks, including Tanzania’s Tarangire National Park, don’t have fences. Wildlife species, including herbivores such as gazelles as well as lions, forage in adjacent lands. This is good for the health of the lions, Pimm says, but it can lead to problems with the neighboring human population.

Pimm is looking into using crowdsourcing in an effort to discover what is happening inside Africa’s national parks and just outside their borders. Crowdsourcing is a new technique that enlists the public to assist with a task. Volunteers interested in assisting the program would monitor a national park and its surrounding region using Google Earth, and note any major changes that occur on the land.

“There’s a huge potential for involving the public in monitoring what is happening to our world,” Pimm says, “particularly what is happening to our national parks, and whether their boundaries are being respected or whether national parks are being destroyed by encroachment from outside.”

Fast Fact

Lions of Gir
Before the last ice age, lions were one of the most abundant mammals on the planet. Lions roamed across the Americas, Asia, and Europe, as well as Africa. Today, only a tiny population survives outside Africa. About 300 Asiatic lions live in a protected area of the Gir Forest in northwest India. See video of the elusive "lions of Gir" here.

Fast Fact

Little Kitties for Big Cats
You and your little housecat can save the big cats! For just $5, National Geographic will publish your cat's photo online to show your support for the Big Cats Initiative. Click here for Little Kitties for Big Cats!

Fast Fact

What Makes a Savanna
Pimm has a definition of Africas savanna. Anything that gets more than about 300 millimeters [11.81 inches] of rain but less than 1,500 millimeters [59 inches] of rain is broadly what we call savanna Africa, he says. And thats where most of the lions are, and thats where most of the people are.

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Stuart Thornton
Jeannie Evers, Emdash Editing, Emdash Editing
Kara West
National Geographic Society
Last Updated

October 19, 2023

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