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Tiger Talk

How studying tiger growls and snorts could help scientists protect the animals

Tina the tiger is something of a celebrity. When fans visit her at the National Tiger Sanctuary in Saddlebrooke, Missouri, she greets them with friendly groans, grunts, and snorts. “People call her the singing tiger,” says biologist Courtney Dunn.

In 2011, Dunn was a volunteer at the sanctuary, which rescues mistreated tigers. She loved listening to Tina and the other tigers make noises. “I wondered what they were saying,” says Dunn.

Tina the tiger is something of a celebrity. Fans visit her at the National Tiger Sanctuary. It’s found in Saddlebrooke, Missouri. It rescues mistreated tigers. Tina greets people with friendly groans, grunts, and snorts. “People call her the singing tiger,” says Courtney Dunn. She’s a biologist.

Dunn worked at the sanctuary in 2011. She loved listening to Tina and the other tigers make noises. “I wondered what they were saying,” says Dunn.

Dunn bought a microphone and began recording the tigers’ sounds. Soon after, she moved to Dallas, Texas, and started an organization called the Prusten Project. (A prusten, also called a chuff, is a tiger’s version of a purr.)

Scientists at the Prusten Project study the sounds of tigers like Tina. They hope their work will help save endangered tigers in the wild.

Dunn bought a microphone. She began recording the tigers’ sounds. She then moved to Dallas, Texas. She started a group called the Prusten Project. (A prusten is a tiger’s version of a purr. It’s also called a chuff.)

Scientists at the Prusten Project study the sounds of tigers like Tina. They hope their work will help save endangered tigers in the wild.

Threatened Cats

A century ago, there were more than 100,000 tigers in the world. They lived across much of Asia (see A Shrinking Home). But over the years, hunters killed many tigers to sell their fur and other parts. Some poachers still do this even though it’s illegal today.

There were more than 100,000 tigers in the world 100 years ago. They lived across much of Asia (see A Shrinking Home). But hunters killed many tigers over the years. They sold the fur and other parts. Some poachers still do this today. But it’s illegal.

People have also cut down forests to make way for farms and homes. This destroys habitat that tigers need to survive. Today, fewer than 4,000 of the big cats remain in the wild. 

Scientists want to keep a close eye on these animals. “Because there are so few tigers left, it’s important to know who they are and where they live so that we can protect them,” says Dunn. 

People have also cut down forests to make way for farms and homes. Tigers need forest habitat to survive. Fewer than 4,000 of the big cats live in the wild today.

Scientists want to keep a close eye on these animals. “Because there are so few tigers left, it’s important to know who they are and where they live so that we can protect them,” says Dunn.

Tracking Tigers

Tigers in the wild can be surprisingly difficult to spot. They roam large territories that are often covered in thick forests. Scientists track the big cats mainly by hiding cameras in trees or bushes. When an animal walks by, the camera snaps a picture. 

Biologists can tell individual tigers apart by the pattern of their stripes. But images from hidden cameras aren’t always good enough for that. “Often you just get a tail or close-up of a nose—or you miss the tiger altogether,” says Dunn.

If scientists could learn about tigers just by listening, it might be easier to track them. That’s why Dunn hopes to use tigers’ calls to monitor the big cats. 

Tigers in the wild can be hard to spot. They roam large areas often covered in thick forests. Scientists hide cameras in trees or bushes to track the big cats. Each camera snaps a picture when an animal walks by.

Biologists can tell tigers apart by the pattern of their stripes. But camera images aren’t always good enough for that. “Often you just get a tail or close-up of a nose—or you miss the tiger altogether,” says Dunn.

There might be an easier way to track tigers. Scientists could learn about them just by listening. Dunn hopes to use tigers’ calls to follow the big cats.

Call of the Wild

Tigers are solitary animals. When they’re not mating or raising cubs, they live alone. To keep in touch with other tigers, they call over vast distances.

One sound tigers use is a booming roar called a long call (see How to Speak Tiger). “It’s incredibly loud—like 22 lawn mowers going at once!” says biologist Emily Ferlemann.

Ferlemann works at the Prusten Project. To study tiger calls, she collects recordings of tigers from zoos and sanctuaries across the U.S. She uses a computer program to create an image that represents each sound. This lets her see the qualities of a call, such as how loud or long it is.

Each tiger’s call makes a different sound picture. Male tigers, for example, have deeper voices than females. Ferlemann says scientists could use these differences to identify tigers. “A tiger’s voice is as unique as your own fingerprint,” she says.

Tigers live alone when they’re not mating or raising cubs. The animals call out to keep in touch with other tigers.

One sound tigers use is a booming roar called a long call (see How to Speak Tiger). “It’s incredibly loud—like 22 lawn mowers going at once!” says Emily Ferlemann. She’s a biologist.

Ferlemann works at the Prusten Project. She studies tiger calls. She collects recordings of tigers from zoos and sanctuaries across the U.S. Then she uses a computer program. It creates an image that represents each sound. This lets her see things such as how loud or long a call is.

Each tiger’s call makes a different sound picture. For example, male tigers have deeper voices than females. Ferlemann says scientists could use these differences to identify tigers. “A tiger’s voice is as unique as your own fingerprint,” she says.

Forest Sounds

Dunn and Ferlemann next want to use their technique to identify tigers in the wild. They plan to hide microphones in the forest to listen for wild tigers. They’ll use the recordings to learn what the calls of individual animals sound like. 

Eventually, a network of microphones could listen for tiger calls throughout an area. Scientists could keep tabs on tiger populations based on which roars they hear where.  

Dunn and Ferlemann next want to use sound pictures to find tigers in the wild. They plan to hide microphones in the forest. They’ll listen for tigers. The scientists will use the recordings to learn what different animals’ calls sound like. 

Eventually, a group of microphones could listen for tiger calls over an area. Scientists would know which animals roared where. Then they could keep tabs on tiger populations.

Microphones would have several advantages over cameras. Cameras can see only what’s right in front of them, but a tiger’s roar can be heard from miles away.

Plus, microphones can record more than tiger calls. “They pick up everything in the forest,” says Dunn. “Birds, bats, frogs, and even humans cutting down trees.” Scientists could use this soundscape to study the health of a whole forest.

Dunn and Ferlemann plan to record tigers in India and Nepal this year. Then they’ll move on to other areas. One thing they hope to learn is whether tiger calls differ from region to region, like human accents.

“There’s more to a roar than you might think,” says Dunn. “These tigers are actually talking to each other.”

Microphones would be better than cameras. Cameras can see only what’s right in front of them. But a tiger’s roar can be heard from miles away.

Plus, microphones can record more than tiger calls. “They pick up everything in the forest,” says Dunn. “Birds, bats, frogs, and even humans cutting down trees.” Scientists could use this soundscape to study the health of a whole forest.

Dunn and Ferlemann plan to record tigers in India and Nepal this year. Then they’ll move on to other areas. They hope to learn whether tiger calls differ between regions, like human accents.

“There’s more to a roar than you might think,” says Dunn. “These tigers are actually talking to each other.”

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