To make sure they understand that there's been a change of ownership, he's introduced a new branding iron: the paw print of a jaguar.
He's also winning them over the old fashioned way, by improving their lives, building schools and clinics.
"There is no better way to stop poaching than to make the local community say, 'Hey, wait a minute, our children have medicine and education because of the jaguar.' When you show that, you've won their hearts and you've won their minds and then you've won the war," Kaplan explained.
Rabinowitz wants the jaguars to be able to roam freely again, so he's working with governments as well as ranchers to protect what he calls jaguar corridors. They connect the different isolated areas where the cats are still thriving. He gets to these areas sometimes, and sometimes he gets too close.
"Now, how far away are you from him?" Simon asked about one close encounter.
"I would say about 20 feet," Rabinowitz remembered.
"And he is standing, sitting, lying?" Simon asked.
"He was standing. Then probably within a few seconds, I realized this is dangerous. And I fell. Of course, you know, what more could happen? So I fell backwards, thinking, 'Okay, if you wanna kill me, now's the time.' I'm on my back. And the jaguar just stood up and started walking off into the jungle. Not very far away," Rabinowitz remembered. "But this is what I'll never forget. It turned back to me, it gave a low growl. It wasn't an aggressive growl. It just gave kind of a low, growling sound, and it looked at me. And I looked at it. And I could look in its eyes now with no fear. And I said to it, I said out loud, 'We're okay now. We're gonna be okay.'"
Rabinowitz can only hope he'll be ok. He conquered his stutter but now he's fighting leukemia and doesn't know how much longer he'll be able to spend in the jungle.
But before we left, he told us he was happy that, after his 30 years of devotion, we'd be introducing so many of his friends on "60 Minutes."