Amadeus Schmidt wrote:
>>Such northern animals *should* have fat, because of uncertain food supply
and for insulation.

An uncertain food supply is not what makes animals fat.  They get fat by
having an abundant food supply.  Animals can and do get fat on grass,
particularly grass at certain times of the year.  There is plenty of grass
on the tundra by the way.  I talked to a grass farmer who fattens his
animals on grass and hay.... they don't gain weight from taking away their
food or providing it irregularly!

Btw:  Modern humans get fat from an over abundant food supply.  How do polar
bears get fat?   They eat a lot of fatty fish.  How do the fish get
fat--they eat plenty of krill and other ocean foods.  The oceans, like the
land, are teeming with life.  They evolved heavy insulation because it's
cold not because the food supply is short.  Shortage of food is not the
cause of fat.  Walruses and seals are fat because of their body structure
and the need for fat to insulate  in the cold.

The eskimos had no shortage of food to eat either.   I think you should read
Jean Auel's books (all four of them) to learn about just how prolific life
is in the absence of modern man and the industrial way of life.  The plains,
tundra, steppes, all supported an incredible array of plants and animals
living symbiotically.  It is a myth that man was constantly on the verge of
starvation and that there was a scarcity of animal food to eat.  ("The
Mammoth Hunters," book #3, goes into a lot of this detail about the kind of
diversity and abundance of life supported by the plants on the steppes and
book #4 goes into even more about herbs, animals, etc.)  Auel's books are
based on abundant research by noted paleoanthropologists.

Cheers,
Rachel & Don,