Interesting - the mention of Neanderthals had me puzzled, so I checked about Altamira, and yes, there is a theory that it was Neanderthals, not homo sapiens, that created (some? or all? of)the works.
https://en.wikipedia.org/wiki/Cave_of_Altamira#Dating_and_periodization
Neanderthals are often though of being more primitive as homo sapiens, but that may not be true: https://en.wikipedia.org/wiki/Neanderthal
a good friend of mine, Bruce Rimmell, had been contributing articles to my website, among them discussing that subject, for example:
https://www.visionaryartexhibition.com/archaic-visions/el-castillo-formative-images-from-the-upper-palaeolithic
New dating that pushed the dates of these paintings further back, Bruce quotes:
“Anatomically modern humans arrived in western Europe around 41,500 years ago and thus may well have made the ancient Spanish paintings. But 42,000 years ago the only humans in Europe were Neanderthals... [Thus] any art there that turns out to be older than 42,000 years must necessarily be attributed to Neanderthals. [Pike & Zilhão] suspect that the red disks and hand stencils at El Castillo might well be Neanderthal paintings, considering that the uranium-thorium dating results are minimum estimates...”