Camels in Genesis Part 1

When my kids being home from school pictures of Avraham wearing a fur-trimmed shtreimal I always let them know that this is an anachronism. Avraham lived in a warm climate, where furry animals would have been in short supply. Though I suppose he could have mailed away to Lithuania for the beaver pelts, there's no indication from the archeological record that Avraham was ever in contact with northern Hasidim. Avraham's hat would have been light and white, and designed to keep the sun off. A shtreimal does the opposite, and would have been useless - if not dangerous - under the hot Cannaite sun.

A similar problem exists in the story of Rebecca at the well. Archeology and the extra-biblical record both sugget that camels were not domesticated in the Middle East until the 12th century BCE. Rebecca's story, unfortunately, occured in the 18th century BCE. The simple answer, then, is that the camels in Eliezer's caravan are an anachronism, added to the story when it was edited and/or (re)written many years later. This is the view celebrated by Bible critics, atheists, and other assorted skeptics.

But not so fast.

Many of the historical details in Genesis are spot on. Horses, which also weren't domesticated until many years later are excluded from the stories. When Avraham buys the Cave of Machpela he deals in weighed silver, not coins. And the rest of Rebecca's story, including the bridal negotiation with an older brother acting as the family's principle agent are consistant with the practices of the period. Absent archeological data, how did a writer many centuries later avoid treating these subjects anachronistically?