Travel Reference
In-Depth Information
The overfl ow of this burgeoning population of microorganisms then
spills over to the last two stomach chambers. There the nutritious organic
acids and fatty acids that the microbes produced during the fermentation
stage are absorbed by their host.
But wait, there's more! The microbes had a high old time as they dined
on all that free food, but now they must pay for their brief Lucullan orgies.
When they reach the acid-fi lled stomach chambers they too are digested, and
their component parts are absorbed by the ruminant's stomach and small
intestine.
The lives of these bacteria are short but (one hopes) happy. And these
characters in our drama have also been shaped by evolution. Ruminants that
have become specialized to eat leaves or grasses carry dif erent specialized
bacterial populations with which they have co-evolved. Each host carries the
right mix of bacterial species to extract nourishment quickly and ei ciently
from their particular type of food.
Hoatzins do not have quite as sophisticated a stomach as the ruminant
grazing animals like cows and sheep. But they do have a two-chambered
crop, the fi rst chamber being an expanded region of the lower part of the
esophagus that leads into the stomach. Most of the fermentation takes place
in the hoatzin's swollen lower esophagus, and most of the digestion in its
stomach.
A primate fermenter
The third member of our cast of characters is a close relative of ours, the
leaf-eating—and leaf-fermenting—proboscis monkey. My most dramatic
encounter with these primate fermenters took place in a vast area of man-
groves and wet rainforest in Kalimantan, the southern part of Borneo.
This Indonesian province comprises the southern three-quarters of the
island. It is the wildest and at the same time the most endangered part of Bor-
neo. Its coasts are home to vast regions of wet lowland forest, and its great
rivers nourish thriving mangrove ecosystems. Both the wetland forests and
the mangroves are threatened by uncontrolled development and logging.
