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How To Count Lions

To protect the iconic African lion, scientists must first get a better estimate of how many there are

Bobby-Jo Clow/Caters News

How many wild lions are in Africa? It sounds like a simple question, but conservationists have spent decades trying to figure it out! There could be as many as 33,000 or as few as 18,000, depending on who you ask—and how they counted.

The elusive animals are tricky to track because they blend in with their environment and often hide from humans. They’re especially difficult to find in areas where poaching is common. Lions also have a huge range, spanning almost all of sub-Saharan Africa. A single lion’s territory can sprawl over 1,000 square miles, which is almost the size of Yosemite National Park in the U.S. So the lion population is very spread out. That’s why lion researchers, like Alexander Braczkowski at Australia’s University of Queensland, are hunting for a new way to count the big cats.

How many wild lions are in Africa? It sounds like a simple question. But conservationists have spent decades trying to figure it out! There could be as many as 33,000 or as few as 18,000. It depends on who you ask—and how they counted.

Lions are tricky to track because they blend in with their environment and often hide from humans. They’re especially difficult to find in areas where poaching is common. Lions also have a huge range. It spans almost all of sub-Saharan Africa. A single lion’s territory can stretch over 1,000 square miles, which is almost the size of Yosemite National Park. That means the lion population is very spread out. That’s why lion researchers are hunting for a new way to count the big cats.

Counting the Ways

Most of the current lion population estimates  are based on three different counting methods. The earliest method, used in the 1970s and 1980s, relied on luring lions with bait. Researchers would catch a lion, tranquilize it, brand it, and release it back to the wild. If they encountered the branded lion again, they would know it had already been counted.

Today, most researchers use either call-up surveys or track counts. To do a call-up survey, “you drive to strategic locations, and you play the calls of a buffalo or a hyena,” says Braczkowski. After hearing the sounds of their prey, “lions run in, and you count each individual.” For track counts, researchers look for lion paw prints on the ground and count each set of tracks they find. Each set of tracks identified is counted as one lion.

The problem with these methods, Braczkowski says, is that it’s very easy to count the same animal several times. There’s no way to know if the same lion comes to multiple call-up surveys, or if multiple sets of tracks belong to the same lion. Track counting is particularly unreliable, as lion tracks may stay visible for a long time in dry environments but vanish quickly after a rainstorm or in windy areas.

Braczkowski is also concerned with how the findings from these counting methods are expanded to estimate populations over large areas. “The bigger assumption these surveys make is that they sample a small area of 200 square kilometers and extrapolate from that out to 2,000 square kilometers,” he says.

Most of today’s lion population estimates are based on three different counting methods. The earliest method was used in the 1970s and 1980s. It relied on luring lions with bait. Scientists would catch a lion and tranquilize it to calm it down Then they would brand it, or mark its skin, and release it back to the wild. If they encountered the branded lion again, they would know it had already been counted.

Today, most researchers use either call-up surveys or track counts. To do a call-up survey, “you drive to strategic locations, and you play the calls of a buffalo or a hyena,” says Alexander Braczkowski. He’s a scientist at the University of Queensland in Australia. “The lions run in, and you count each individual,” he says. For track counts, researchers look for lion paw prints in the field. They count each set of tracks they find as one lion.  

But both of these methods have a problem, says Braczkowski. It’s very easy to count the same animal several times. There’s no way to know if the same lion comes to multiple call-up surveys, for example. Scientists also can’t tell if multiple sets of tracks belong to the same lion. Track counting is particularly unreliable. That’s because lion tracks may stay visible for a long time in dry areas but disappear quickly if it’s rainy or windy.

Braczkowski is also concerned with how people use the numbers from these counting methods. Researchers often multiply them to estimate populations over large areas even though most of those areas weren’t actually surveyed. “They sample a small area of 200 square kilometers and extrapolate from that out to 2,000 square kilometers,” he says. But there may not be the same number of lions in every part of that range.

By a Whisker

Braczkowski and his colleagues have been testing a new way of counting lions that they think will provide a better estimate of how many there are. It’s called spatially explicit capture-recapture (SECR). It’s already gaining popularity with researchers and agencies such as the Kenya Wildlife Service. SECR tracks specific animals’ movement patterns using traditional photography and drones. With that data, they identify lions based on their whisker patterns. Each lion has a unique whisker pattern, just like human fingerprints are unique. So no lions are counted twice.

With this method, scientists can study how the cats they’ve photographed behave in the wild. They can monitor lions’ gender ratios, where each lion travels, and more. Because SECR is done over a small area for multiple years, it can be used to build reliable population models too. “It tells you if your population is rising, decreasing, or stable,” says Braczkowski.

SECR’s strength is also its drawback. It’s much more time-intensive than other methods, because it has to be done over a period of years. And because each lion has to be identified by its whiskers, it works only for groups of lions that can be photographed.

Braczkowski and his colleagues have been testing a new way of counting lions. They think it will provide a better estimate of how many are left. It’s called spatially explicit capture-recapture, or SECR. It’s already gaining popularity with researchers and agencies such as the Kenya Wildlife Service. SECR uses photos from cameras and drones to track specific animals. The images help scientists identify lions based on their whisker patterns. Each lion has a unique whisker pattern, just like humans have unique fingerprints. So no lions are counted twice.

With this method, scientists can learn how the cats they’ve photographed behave in the wild. They can monitor how many lions are male and female, how each lion travels, and more. Scientists use SECR over a small area for multiple years at a time. That makes it a reliable way to tell how a population is doing. “It tells you if your population is rising, decreasing, or stable,” says Braczkowski. 

SECR does have drawbacks. For one, it takes much more time than other methods, because it has to be done over a period of years. Identifying each lion by its whiskers also has limits. It works only for groups of lions that scientists can find and photograph.

Big-Cat Baseline

Why is it important to know how many wild lions there are? It’s the key to conservation, says Braczkowski. “If you cannot track threatened species’ populations over time, you don’t know how good your conservation interventions are at helping,.”

Scientists don’t know how many lions are left, but they do know that the lion population has fallen dramatically in the last 120 years. The big cats have vanished from 90 percent of their historical range, which could represent a population drop in the hundreds of thousands. A more accurate count can help lion conservationists ensure the iconic cats survive in the wild.

“Establishing good monitoring programs should be the gold standard,” says Braczkowski. “If we don’t do that, we’re selling ourselves short.”

Why is it important to know how many wild lions there are? Braczkowski says it’s the key to protecting them. “If you cannot track threatened species’ populations over time, you don’t know how good your conservation interventions are at helping those animals,” he says.

Scientists don’t know exactly how many lions are left. But they do know that the wild lion population has fallen dramatically in the last 120 years. The big cats have vanished from 90 percent of their historical range. That could mean their population has dropped by hundreds of thousands. A more accurate lion count can help conservationists make sure the big cats survive in the wild. “Establishing good monitoring programs should be the gold standard,” says Braczkowski. “If we don’t do that, we’re selling ourselves short.”

Determine which sampling method from the list is used to gather data about lions in the following scenarios. Record your work and answers on our answer sheet.

Determine which sampling method from the list is used to gather data about lions in the following scenarios. Record your work and answers on our answer sheet.

Brit Finucci/Getty Images

    After photographing and identifying them by their whisker pattern, researchers assign each lion a number. A researcher collects data on how far each lion travels. In her report, she uses data from the lions whose assigned number is a multiple of 3.

    After photographing and identifying them by their whisker pattern, researchers assign each lion a number. A researcher collects data on how far each lion travels. In her report, she uses data from the lions whose assigned number is a multiple of 3.

Tony Karumba/AFP via Getty Images

    A researcher gathers lion tracker data within a 2-mile radius of his research camp.

    A researcher gathers lion tracker data within a 2-mile radius of his research camp.

iStockPhoto/Getty Images

    A researcher determines the number of lions  in an area based on how many of them respond to an injured hyena’s call played over a loudspeaker.

    A researcher determines the number of lions  in an area based on how many of them respond to an injured hyena’s call played over a loudspeaker.

Sebastian Kennerknecht/Minden Pictures

    Lions are divided into groups based on their paw size. A researcher randomly selects the group with the largest paws to gather data from.

    Lions are divided into groups based on their paw size. A researcher randomly selects the group with the largest paws to gather data from.

Konrad Wothe/Minden Pictures

    Lions in a reserve are grouped by age. A researcher randomly selects 5 lions from each age group to collect data from.

    Lions in a reserve are grouped by age. A researcher randomly selects 5 lions from each age group to collect data from.

Which sampling method do you think provides the strongest data? Explain your reasoning.

Which sampling method do you think provides the strongest data? Explain your reasoning.

Choose a sampling method. On a separate sheet of paper, write your own research scenario using that method. Explain how your scenario demonstrates your chosen method.

Choose a sampling method. On a separate sheet of paper, write your own research scenario using that method. Explain how your scenario demonstrates your chosen method.

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