"Absolutely," he replied. "So, really, dinosaurs never went extinct."
"Dinosaurs never went extinct. But we all think they did," Stahl said.
"There was an asteroid event that took out a lot of life on Earth, including T. Rex and all the most famous dinosaurs. But this other group, what we call birds, made it through and of course, there's thousands of species of birds still around today," Carroll explained.
The dinosaur-bird connection is largely settled now, but that hasn't stopped Horner from using unusual means to make unusual discoveries, and he has found the perfect partner in his protégé Mary Schweitzer. She's a professor at North Carolina State who studies the internal makeup of ancient bone.
She let us in on the paleontologists' trick for telling dinosaur bone from rock.
Instead of looking at it, you're supposed to lick it, and she encouraged Stahl to participate in the experiment.
"It's supposed to stick like Velcro. Does it stick?" Schweitzer asked, as Stahl put the dinosaur bone to her tongue.
"Ah, ew. It did," Stahl replied.
Asked how this works, Schweitzer said, "Because the bone's filled with little capillaries. And when you put your tongue on it, the moisture from your tongue sucks out the capillaries. … Rocks don't do that."
The tricky thing about Schweitzer's work is that she needs to get her hands on the insides of dinosaur bones, which means literally breaking the bones apart and sometimes dissolving pieces of them in acid. Most paleontologists won't let her near their precious finds.
"Jack [Horner] is the only paleontologist out there who lets me dissolve his dinosaurs," she told Stahl.
It means ruining the bones.
"Isn't that considered a little sacrilegious to…take one of these precious artifacts, fossils that have been in the ground for 68 million years and crack it in half?" Stahl asked Horner.
"We found the first dinosaur embryos, the first babies inside of eggs. And it was just from breaking eggs open and looking inside. I mean, people had always thought that eggs were so precious, they didn't wanna break them and look inside. And yet, they're like presents. You know, I mean, it's like having a Christmas present and never unwrapping it," he replied.
"Did you ever, though, have a moment where it was kinda heartbreaking? You know…'I'm destroying.' Never?" Stahl asked.
"No," Horner said. "Glue is cheap."
Horner's practice of breaking dinosaur bones apart and sending the insides to Schweitzer has landed the two of them at the center of one of the biggest controversies paleontology has seen in years.
It started back in 2000, with a series of coincidences. A member of Horner's team, Bob Harmon, wandered away from a dig site one day to eat lunch, and noticed a small piece of bone sticking out of the side of a 50-foot cliff.
"I could tell pretty much what it was from where I was sitting. It was a T. Rex metatarsal," Harmon recalled.
Horner named the T. Rex "B. Rex" in Bob's honor, and made the decision to dig it out.