It's all about energy efficiency. And depending on the context.

Think MovNat. Look at all the videos from MovNat.

Kipping vs strict pullup is a false dichotomy. So much more ways to get yourself on a tree branche.

Probably he would have. If it was part of a daily activity like climbing a mountain he wouldn't have worried about how many strict pullups he can do during crossfit.

lol. I thought about this too when I started doing crossfit (back before it was the hot new thing, and I got some pretty insane looks at the gym doing kipping pull ups and handstand pushups) Here was my thinking- in order to make a movement applicable, you do it in a way that engages the entire body so that that movement can be applied to a variety of situations and scenarios. If you do a movement to isolate a particular muscle group, you strengthen the muscle group, but the movement may or may not be able to be applied when it is needed. Kipping pullups vs traditional pullups are like front squats vs a leg press machine. Both built stregnth, but one is more useful, practical, applicable than the other

I went to an indoor rock climbing gym for several years and had the opportunity to climb outside on a handful of occasions.

Climbing a large, imposing rock seems to be the best analog to a Pleistocene/Paleolithic "pull-up" (although I suppose tree climbing would work as well.)

When facing the option of either falling down a rock face, or making it to the top, I most definitely did anything and everything that I could. If "kipping" was an option, I would have taken it gladly. As it was, I performed a move that could more accurately be described as "the beached whale".

This involves applying as much bodily surface area as possible to the rock and, inch by inch, shimmying until enough body mass was over the lip to permit a muscle-up-esque top-out of the boulder.

Hold on just a second here.

Everybody loves pullups, which is all well and good. But I'm having a hard time imagining paleo man regularly pulling himself up to something. Am I missing something? Survival is partly about risk avoidance, and humans are not the best tree-climbers or cliff-hangers-on'ers.

Picking stuff up and carrying it seems very natural. So deadlifts, farmer's walk, odd lifts in the fashion of old-timey strongmen. Making stuff is natural. So repetitive smashing, yanking, etc. Pushing things and pulling things too, so pushups and horizontal rows mimic things nicely. But pullups? Again, nothing against that most sacred of sacred cows, the pullup and chinup.

If paleo man were to perform a pull up (to get into a tree or something) but did not have the strength to do so, he would kip.

Not unless he was trying to pull himself over a cliff to hunt down a deer.

I hate kip pull ups. They are unnatural to attempt. So I doubt cavemen would have don them, or classic pull ups for that matter.