It’s hard to believe that I’ve been bringing animals onto David Letterman’s show for 30 years now. My last appearance on Dave’s show—which was April 29—has been on my mind constantly for the past few weeks. What could I do to make the show special? Should I try to be funny? How could I adequately convey my appreciation to Dave and the team? What animals should I choose?

I never could have imagined that my career would involve sitting beside sloths and snakes on a late-night TV couch. In 1978, I was hired as the director of the Columbus Zoo, and I did everything I could to transform the outdated zoo into something the community could be proud of. Then two rare twin gorillas were born at the zoo in 1983, and my world changed. Good Morning America featured the birth, which put our zoo on the national map. And several months later, one of Letterman’s bookers, Laurie Lennard—now Laurie David—reached out to our producer at GMA for my contact information. When they called my office, I accepted without hesitation. I had watched Johnny Carson, and late-night TV seemed like fun. I thought it would be a good opportunity to educate audiences about animals. In retrospect, I was enthusiastically naïve, but luckily it all worked out. 

Our first trip to New York was an eventful one: A huge snowstorm canceled our plans to drive into the city. But I knew that if I called Letterman’s people and said I couldn’t make it, my chances of being asked back were slim. Fortunately, a Columbus Zoo board member came to the rescue and let our 85-pound baby pygmy hippo board his private plane so we didn’t miss the show after all. It was the first and only time I’ve brought a hippo to a show.

As the hippo and I sat backstage getting ready to go on, someone asked if I was nervous that Dave would eat me alive. “Why would I be nervous?” I asked. She just looked at me and laughed. 

That was the first time Dave and I met: on the air, Feb. 14, 1985. I was lucky—he took it easy on me. He was more polite than I anticipated, though I do remember him looking at me like I might be a little crazy. In all fairness, he still does that. The show must have gone well, because the producer asked us back. We never did rehearsals with Dave and I think that is one of the major reasons it worked: His genuine, unbridled reactions are priceless. 

One of our most chaotic appearances happened soon after our first show, when I brought a couple of full-grown camels to the city. I weighed and measured them, but I forgot to measure the height of their humps. As we walked down the hallway to the studio, their humps took out just about every ceiling panel—ruined them, lights and all. I never noticed that they had a camera rolling during the whole fiasco and that Dave was going to open the show with it. Thankfully it was a big hit, and no one was hurt. Dave then rode one of camels and almost knocked his head on one of the studio spotlights, but otherwise the show went great. 

In 2014, I decided that we should revisit camels after all these years. So I brought one to the studio and attempted to ride it myself this time. Though we managed not to tear the building apart, I almost broke my kneecaps. Apparently, camels and Letterman are a bad combination.

In all these years, I’ve only had one scary incident on set: In December 1988 I was bitten by a beaver. As I got up to take the beaver offstage during the commercial break, she started to slide out of my hands. I grasped the base of her tail with my right hand, and she chomped down on the space between my left thumb and index finger. But the show must go on, so I stuck my hand in a rubber glove so I could return to the stage. As we finished the segment, the glove on my hand was rapidly filling with blood.

Since it was Christmas time, there was no chance I would get a cab, so I literally ran to Roosevelt Hospital. Once there, people were horrified by the blood spattered all over my clothes. Of course, the first question was, “What happened?” I didn’t want to tell them that a beaver bit me on David Letterman’s show, so I improvised. “My beaver bit me in Central Park.” I’m not sure they ever believed me, but they patched me up just the same.

There are so many memorable moments from over the years: like the time two armadillos tried to mate on Dave’s desk, or when a Eurasian eagle owl flew high up in the rafters on camera. Just recently Dave even allowed one of our hawks to land on his head. But for every funny moment, there were also heartwarming, endearing moments, particularly when we featured some of Dave’s favorite animals. He’s never met a cat he didn’t ooh and ahhh over.

Dave has done more for the animal world than he realizes. He has introduced his audiences to animals they might never have even heard of. I am really going to miss seeing Dave and the whole Letterman team regularly: from the producers and the crew to the band. At this point, they all feel like family.

For my final time on Letterman, I decided on a laughing kookaburra, two hyenas, two alligators, two baby servals, and two baby clouded leopards—Dave does love cats, after all. His interest in animals has grown considerably over the past 30 years. Over time, he started asking more in-depth questions and you could tell he was reading up on his animal guests.

In all these years, after more than 100 appearances, I’ve only seen Dave before the broadcast twice. On Feb. 2 and April 29, Dave’s family came by the green room before we filmed. That night in April, my wife, Suzi, and I had a few moments to chat with Dave, his wife Regina, and their son Harry. We reminisced about our time on the air together, and then he went onstage. He opened our segment by showing me a picture of animal tracks and asking me to identify them. Luckily, I came up with the right answer: wolverine. “Wolverines are amazing animals, aren’t they?” Dave said. He probably knows more than I do about animals by now—as he likes to say, I am a “walking encyclopedia of misinformation.” From Dave’s kookaburra noises to the retrospective montage to the hyena drinking water out of his mug, our last show together was perfect.