Traditionally, the weavers of all the Rio Grande Pueblos have been male, with the exception of the Zuni. So it's often explained that among the Navajo it's the women who weave because they learned it from the Zuni women.
But it's not clear why, perhaps, it couldn't be the other way around, or why the Navajo couldn't have learned it from one of the other Rio Grande Pueblos. Someone had to be the first to be different, and it might just as well have been the Navajo, who were known to borrow, adapt, or innovate whatever worked for them. But I have to admit I know next to nothing about Zuni tapestries, so I can't disprove the standard hypothesis.
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