At 75, American biologist George Schaller has spent his life studying wild animals in more than 25 countries: mountain gorillas to snow leopards to alligators to caribou. It was he who inspired the primatologists Jane Goodall and Dian Fossey, for example. Schaller is the recipient this year of the $100,000 Indianapolis Prize, the world's top award for animal conservation. In another of our weekly series, Carolyn Weaver reports on a man who has long been "making a difference."

Biologist George Schaller, a founder of the modern wildlife conservation movement

Mountain gorillas were Schaller's first great subject. In 1959, at the age of 26, he moved to Central Africa to live in the wild with the little-known beasts.

"The biggest task was to observe the animals so they don't run away. So, you slowly get them used to you until they see:  'Oh, there's that Schaller again,' and forget it, and go on with their normal life. And that's the way you want it," he said.

That was the beginning of a lifetime of discoveries. In the 1970's, Schaller became one of two westerners to see a snow leopard in Nepal, not seen by outsiders in nearly three decades. In 1988, he and his wife were the first westerners allowed into China's Chang Tang region, to study giant pandas. Schaller and another biologist discovered a new species of goat in Laos in 1994.

Mountain-gorillas Little was known about the life of gorillas in the wild until Schaller published The Mountain Gorilla in 1963 (Photo: Mike Crowther)

Yet Schaller says the pleasure of studying animals is not his primary motivation. He says it's conservation that matters most.

"If you really love something, if there's something that should remain as a country's natural heritage, you have to keep fighting forevermore," he said. "Everything we have, this whole so-called civilization, is all dependent on environment: on the clean air, the water, the soil, the food. And unless communities start fighting for a healthier environment around them, there's not much hope."

Schaller was in New York recently to receive the Indianapolis Prize, given by the city's zoo for conservation achievement.

"He's the George Washington of conservation biology," said Zoo president Michael Crowther said. "There are generations of people now who grew up learning about conservation from George Schaller."

And Schaller says he'll use his $100,000 Indianapolis Prize to train local conservationists around the world.

"They will train people who then have students, so, generation after generation, the little bit that we started from, will increase in the country," Schaller said. "And so, you leave something behind that will be valuable, long after everyone's forgotten me."

Some video courtesy of Wildlife Conservation Society