Hi, Richard.  You wrote:


>An article about two years ago in National Geographic on the life of
Orangutans (I think) had a nifty graph of the ketone levels in the
Orangutan's blood throughout the year.  They go through a yearly cycle.
They fatten up when fruit is plentiful, and thin down when it is not.  Their
reproductive cycle is in sync with this so they reproduce at the peak of the
fat cycle.
>
>I assume a HG goes through the same cycle.

Strange you should think of that article.  I had just looked it up again
last night.  The article is in the August, 1998 Nat Geog.  One section, Boom
or Bust, says, "Their movements are highly influenced by the presence of
ripe fruit."  A map showed how their paths differed during fruit-poor and
mast fruiting periods.

"During fruit-poor periods the apes often ranged more widely between
habitats while searching for food."  Their diet during a mast fruiting is
higher in calories than at other times, due to a higher carbohydrate and
lower fiber content.

"The low-fruit period:  When high-calorie fruit is not readily available,
orangutans rely on less nutritious but relatively plentiful foods, such as
leaves, figs, ginger stems, and the inner layer of bark.  Low fruit periods
can last for months."

The article explains that during lean times, the males often descend to the
ground to suck termites from their nest.  They also eat bark, leaves  and a
celery-like plant.

"As with humans, orangutans store fat when food is abundant.  By measuring
the byproducts in their urine, I've found that during periods of scarcity
they produce ketones - telling me that they are burning up their fat
deposits.  The extra calories they stored when fruit was plentiful are now
helping them survive."

Kath