>One of Daniel Quinn's books (either "Ishmael" or "Story of B," I forget
>which) mentions that some of the plains Indians were agricultural for a
>time, and they became hunter/gatherers again after they learned from the
>Spanish how to use horses.  Maybe that explains the other blood types?

That's a good point, but I doubt that an agricultural period would account
for 76.5% (if I recall correctly) of the Blackfoot and Blood being Type A.
In the first place, >75% Type A is highly unusual, even in European
countries where agriculture was prevalent.  Secondly, I can't find any
evidence that the Blackfoot and Blood tribes ever relied on agriculture,
though I could be wrong.  Are any of the subscribers to this list well
versed in Native American history?  I found the following information on the
HotWired Network:

<<To the west of the Iroquois, between lakes Superior and Winnipeg, lived
the Ojibwa, forest hunters who learned to cultivate maize from the Iroquois
and also harvested the wild rice that grew on the fringes of the region's
lakes.

Further west still, on the prairies, lived the peoples of the Blackfoot
Confederation: the Piegan, Blackfoot and Blood tribes. The economy of this
grouping was based on the bison: its flesh was eaten; its hide provided
clothes and shelter; its bones were made into tools; its sinews provided bow
strings; and its hooves were melted down to provide glue. In the late
seventeenth century, the hunting techniques of these prairie peoples were
transformed by the arrival of the horse, which had made its way - either
wild or by trade - from Mexico, where it had been introduced by the Spanish
conquistadors. The horse made the bison easy prey and, as with the Iroquois,
a ready food supply spawned the development of a militaristic culture
centred on the prowess of the tribes' young braves.>>

So, it seems that, while some of the tribes relied on agriculture (such as
the Ojibwa), the Blackfoot and Blood were still dependent on bison when the
Spanish arrived.

-- Aaron Wieland