Growing up in suburban Boston, Jeff Corwin could have easily been more city kid than nature buff. But the naturalist-turned-TV star, now in his 12th year in front of the camera, developed an early affinity for the natural world.

Growing up in suburban Boston, Jeff Corwin could have easily been more city kid than nature buff. But the naturalist-turned-TV star, now in his 12th year in front of the camera, developed an early affinity for the natural world.

Corwin’s childhood, which included hunting tadpoles at a local golf course, sparked an obsession that would later spawn a highly successful career as a conservationist and entertainer.

Every continent and countless species have been shown on his Animal Planet shows, "The Jeff Corwin Experience" and "Corwin's Quest." Although the show is antics-filled, Corwin’s latest project is more of a rescue mission than a fanciful romp.

The Marshfield, Mass., resident, who juggles two TV series while raising two daughters with his wife, Natasha, has focused his career on bringing the planet’s most vulnerable species back from the brink of extinction.

Writing his latest book, "100 Heartbeats: The Race to Save Earth’s Most Endangered Species,'' was a sobering experience for the lifelong conservationist.

"We failed,'' said Corwin, who spent a year compiling stories of the most endangered creatures and the scientists devoted to saving them. An accompanying two-hour documentary will be shown Sunday on MSNBC.

The book’s title refers to those species that have fewer than 100 individuals left. It’s a concept Corwin read about decades ago, but he never expected to become a reality.

"These are real-life battles,'' he said. "This is the reality of our world now,  and I hope the book is a wake-up call.''

After more than a decade as TV’s "animal guy,'' Corwin focused his mission after the harsh reality of extinction set in. Species he had filmed throughout his career had since vanished, and several of the animals he had taught his children to appreciate were nearly gone.

Preserving the Earth for his daughters, Maya, 6, and Marina, 13 months, became a priority.

"It terrified me to know that my daughters would not inherit the same Earth that I did,'' Corwin said. "Ultimately, we are punishing the next generation.''

Corwin’s drive to inspire the next generation was palpable before he had his own children.

In 1999, he focused his attention on Boston's South Shore. He approached the people at the South Shore Natural Science Center about creating an exhibit.

The center’s naturalists, who had a hand in cultivating his love of nature when he was a boy, helped plan the exhibit and raise money for it. The result was the EcoZone, an interactive exhibit that explores the natural wonders of the North River system.

His efforts got others interested in natural treasures that are often overlooked, said Martha Twigg, executive director of the science center.

"With all of his experience globally, he still comes right back to what’s here,'' Twigg said. "When somebody of that exposure does that, it does make you turn around and look at what you have.''

Having a two-hour prime-time slot on a major news network is more than just a career-building step for Corwin. He said it gives him a chance to plead his case before a broader audience.

"I’ve been waiting for 42 years to do this,'' he said. "We don’t have the luxury to sit back and let someone else deal with this anymore.''

Kaitlin Keane may be reached at kkeane@ledger.com.