Robert Irwin Opens Up About His Dad, Dancing with the Stars, and That Underwear Ad! (Exclusive)

Robert Irwin, the son of the late Crocodile Hunter star Steve Irwin, knows he’s happiest when he’s outdoors playing with animals — like for his recent PEOPLE cover shoot, where he cuddled up with kittens, ducklings, llamas and horses at a Los Angeles ranch.

“No desk job for me,” the 21-year-old says with a laugh. “I’d rather play with crocodiles all day. Or be surfing, skydiving, skateboarding, mountain biking, rock climbing . . . I think it’s the Irwin genetics. I was just born to be wild.”

Irwin, who usually works as a wildlife conservationist at the family’s Australia zoo alongside mom Terri, 61, sister Bindi, 27, and brother-in-law Chandler Powell, 28, is in L.A. for the time-being to compete on this season of Dancing with the Stars (premiering Sept. 16 on ABC). The big move comes 10 years after his older sister Bindi won the Len Goodman Mirrorball Trophy in 2015.

“Dancing with the Stars scares me more than anything else I’ve ever done! I’ve never attempted anything close to dancing. I guess you could say that avoiding a crocodile trying to eat you requires footwork, but it’s different,” he says.

But Irwin, whose birth was literally filmed in his dad’s show The Crocodile Hunter, is all grown up — and ready to tackle new challenges.

“I’m at a time in my life where I want to branch out and try as many new things as I can,” he says.

That includes modeling — in April, his campaign for Bonds underwear caused a massive stir owing to Irwin’s grown-up look (and chiseled abs!). He laughs at the reaction it got, and jokes that getting into shape for it required “way too many sit-ups.”

“I did not expect the reaction it got!” he says with a laugh.

But he says, it was worth it.

“Yes, I’m all grown up, and I want to start tackling bigger projects and discussing the big and important issues,” he says. “I feel like my whole mission of conservation is being listened to on an even larger scale, and it’s more important than ever to come together with a sense of kindness toward each other and toward the planet. ”

Other new challenges, of course, include being on this season of Dancing with the Stars.

“I wanted to do this because I was inspired by my sister Bindi, who won Dancing with the Stars 10 years ago,” he says. “I remember coming to every live taping to watch her and thinking, ‘One day I have to do this.’”

He can’t say how long he’ll last, but he’s training hard with his partner Witney Carson. “I may not have the skills, but I’ve got the passion!” 

Irwin says his sister and mom Terri will be in L.A. with him during the duration of taping, and he’s thrilled to have them by his side.

 “We’re so tight-knit,” he says of his clan.

“We’ve been together through thick and thin and really have each other’s backs. The biggest guiding light in my life is my mom. She is just the bravest, most steadfast, determined human being I’ve ever met,” he shares. “To me, she is the epitome of a great leader, a great mother, a hero. She built this life with my dad, and she had the rug pulled out from under her, but was able to pick up the pieces with such grace and still be there for my sister and me.”

Irwin was just 2 years old when his dad was killed during a freak accident. On Sept. 4, 2006, the wildlife conservationist was pierced in the chest by a stingray’s barb while filming in the Batt Reef off the coast of Australia.

Despite his crew’s efforts to save his life, The Crocodile Hunter host died at 44 years old. Though Robert notes they didn’t have much time together, he says his dad is still his guiding light, and the family speaks of him daily.

To read more about Robert Irwin, pick up the newest issue of PEOPLE on stands Friday

“My dad exemplified what it was to truly live,” he says.

“He’s still part of every day, every conversation,” Robert adds. “I feel as though I get a little piece of him back in everything I hear about him or each photo I see. I have an even greater picture of who he was now that I’m reaching the same milestones he did as a young bloke. I feel closer to him, I really do.”

“I think losing someone as important as him at such a young age solidified the idea that life is fragile,” he shares. “We don’t know what tomorrow holds, so you have to take calculated risks, you have to have fun, enjoy what you’re doing, and give everything 100 percent.”

That’s exactly what he’ll do on DWTS, but when the show is over, he’ll be just as thrilled to get back to his conservation efforts.

“I really feel as though I’m on this planet for a reason, and I wake up every day with a sense of urgency, with a fire in my belly, just thinking I need to make the most of every second,” he says.

“Life is so short, so we owe it to ourselves to do what we love. I recognize that I’m in a very unique, privileged position in that I found my calling early. I was born into it. But I truly love what I do.”

Dancing with the Stars season 34 premieres Tuesday, Sept. 16, at 8 p.m. ET on ABC and simulcast on Disney+. The show streams the next day on Hulu.