There are a lot of theories about why cave art was done. The reasons people created cave art, figurines, and other things we call “art” is probably more complex than we can understand, especially since there was not written anything to tell us why the creations were made. Some theories about the purpose of early art are that it was art for art’s sake, meaning that it was created purely to be something nice to look at, that it had no function other than to be art. Another theory is that they were meant as language, such as with hieroglyphs where images are used in the place of letters. If this is the case, then it would have to be similar to the depictions used in Egypt before hieroglyphs, the system that gave birth to hieroglyphs. Cave art does not seem to be as advanced as hieroglyphs, but could very well be a type of language, especially taking in the dots that often appear. Some say it was used for hunting magic, that the art gave the artist some kind of connection with the animals. They could have something to do with male/female initiation rituals, evidence for this is the presence of child-sized and adult-sized hand-prints and footprints. They could have been used for shamanistic purposes or for rituals of increase, to increase fertility so they could have children, to increase the amount of animals for them to hunt, etc. Finally the paintings could be markers of places used for gatherings. I think all of these theories have good arguments, yet they all also have holes. Until we learn more, it is impossible to say one way or another what exactly they were used for.
The artists who made these paintings had great skill. The paintings are beautiful, and they were created with minimal supplies compared to today. Personally, I have no artistic ability, I can’t even draw a chair and make it look natural. For these people to be able to draw things they saw in 3D as 2D paintings is amazing. Especially since at first, they would have had no other 2D paintings to copy. I can’t even imagine what kind of changes human thought processes must have gone through in order to be able to start creating these pieces of art.