For good climbing, I'd have thought you need to be able to do muscle-ups (pullups that end with you balanced over the bar, pushing down to support yourself).

For some styles of climbing powerful muscle-up type dynamic movements are an effective way of solving a problem.

Climbing is adaptive, and usually there is more than one way to solve a problem, and one is encouraged to use their body any way they can to get through a section. Many elite climbers have distinctive trademark styles and are instantly tecognizeable just by how they move.

Jan Hoyer is an outlier who posesses both a freakish abundance of power and span. He trained the muscle up to outrageous extremes.

Jan is the only climber to ever throw a 1-9 on the campus board. He performs many outrageous stupid climber tricks throughout this 8 minute video;

https://youtu.be/Ho_rzpQGrq8

That's probably a level beyond where the majority of people who frequent the climbing gym get to. Even pro climbers might not be able to do any muscle ups.

Here's Alex Honnold talking about it: https://www.youtube.com/watch?v=kDUeh8nyLT0&t=490s

He demonstrates he can only do 5 pullups (though it's possible he was being modest).

Thanks - my preconceptions about climbing are corrected! (A little.)

Climbing is less about upper body muscle and more about body positioning and squats, actually. Your legs have more muscles than your arms, and being super buff limits necessary flexibility to perform maneuvers like swinging your foot up on a perch and pulling up with your leg, often more effective than the same maneuver with an arm.

Climbing is also about core strength. I started bouldering much more regularly about a year ago, and was amazed by how much my trail running improved without any special effort.

At a beginner level, maybe. As you get past beginner levels, you need strength… especially upper body strength.

Rock climbing is especially upper body strength intensive. It’s why the guys have ripped upper bodies and tiny legs.