"Finally, if a myth or religious custom is attested in India but not in the other IE cultures, this need not mean that the Indians have borrowed it from “pre-Aryan natives” or so. It can also mean that the other Indo-Europeans have lost what was originally a pan-IE heirloom. All of them have started by going through the same bottleneck, passing through Afghanistan, immediately plunging themselves into a very different climate from India’s permanent summer, so that they had to adopt a very different lifestyle. And as they moved on, the difference only got bigger. Of practically all IE myths attested in some IE cultures, we know that they have been lost in other (generally in most) IE cultures; it is statistically to bib expected that some myths have survived only in the Hindu tradition. And because of the full survival of Pagan religion in India plus the long centuries of literacy, it is in fact to be expected that a much higher percentage than the statistical average has only survived in India. So, probably, some myths attested only in Hinduism are purely IE, and if they are also attested in a non-IE neighbouring culture, the possibility remains that the latter has borrowed it from the Indo-Europeans."