I'm taking a mythology and folklore class, and in our first reading assignment the text makes the claim that Herakles is "almost certainly" a holdover from paleolithic mythology about hunting. They support this claim by saying "He is dressed in animal skins, and carries a club, like a caveman."
The footnote points to a book by Walter Burkert, Greek Religion, but I can't seem to find any relevant text excerpts, or even an academic assessment of Burkert's credibility.
Can someone shed some more light on this? I'm sorry if this isn't the right sub for this question.
The relevant bit of Burkert's book is section IV 5.1 (pp. 319-24 in the 2nd edition; pp. 208-211 in the English translation, especially p. 209). Burkert is an extremely reliable writer, but the text you're reading does not represent him accurately: Burkert makes it quite clear that this is only supposition. Here's what he actually writes:
Überhaupt gibt es auf Rollsiegelbildern des 3. Jahrtausends einen Helden mit Löwenhaut, Bogen und Keule, der Ungeheuer überwindet, Löwen, Drachen, Raubvogel; man identifiziert ihn als Ninurta oder Ningirsu, Sohn des Sturmgottes Enlil. Der Kern des Herakles-Komplexes dürfte indes noch wesentlich älter sein: Das Herbeiführen der essbaren Tiere weist bis in die Jägerkultur zurück, und die Beziehung zum Jenseits mit Sonnenrindern, roter Insel, Menschenfressern gehört wohl zu schamanistischem Jagdzauber, mit dem auch die jungpaläolithischen Höhlenmalereien zusammenzuhängen scheinen.
(official translation) Furthermore, cylinder seals from the third millennium often show a hero with lion skin, bow, and club, who slays monsters, lions, dragons, and birds of prey; he is generally identified as Ninurta or Ningirsu, the son of the storm god Enlil. The core of the Heracles complex, however, is probably considerably older still: the capture of edible animals points to the time of the hunter culture, and the relation to the world beyond with cattle of the sun, a red island, and man-eaters probably belongs to shamanistic hunting magic -- something which also seems to be reflected in the cave paintings of the Upper Palaeolithic.
In your text, Burkert's references to early Bronze Age iconography of Near Eastern figures have become Palaeolithic "mythology"; his "probably" (dürfte sein) has become "almost certainly"; and his parallels with Palaeolithic art have turned into parallels with cartoon cavemen.
As it happens I would be very hesitant about accepting even Burkert's word on the supposed Palaeolithic material. He's only talking in generalities, for one thing; for another, he's certainly not talking about Herakles himself, but about distantly-related figures from whom Herakles inherited his mythological paraphernalia; and third, in historical-era Greek mythological texts there are plenty of parallels for the idea of casting someone as backward and/or uncivilised by giving them characteristics that carry a flavour of hunting, meat-eating, and a lack of civilised customs, so there's more than one reason for Herakles' iconography, and no way of weighing up their relative importance.