On Food and Cooking

Around 30 million years ago, the earth’s
warm, moist climate became seasonally arid.
This shift favored plants that could grow
quickly and produce seeds to survive the dry
period, and caused a great expansion of
grasslands, which in the dry seasons became a
sea of desiccated, fibrous stalks and leaves. So
began the gradual decline of the horses and
the expansion of the deer family, the
ruminants, which evolved the ability to
survive on dry grass. Cattle, sheep, goats, and
their relatives are all ruminants.
The key to the rise of the ruminants is their
highly specialized, multichamber stomach,
which accounts for a fifth of their body weight
and houses trillions of fiber-digesting
microbes, most of them in the first chamber,
or rumen. Their unique plumbing, together
with the habit of regurgitating and rechewing
partly digested food, allows ruminants to
extract nourishment from high-fiber, poor-
quality plant material. Ruminants produce