RUMINANTS

RUMINANTS
Animals having a rumen - a large digestive vat in which fibrous plant material is partially broken down by microbial fermentation, prior to digestion in a "true" stomach (the abomasum). There are also two other stomachs - the reticulum and the omasum. Typical ruminants are cattle and sheep.

mammal which chews cud, such as a cow or deer; chewing cud.

For the most part, the digestive system of ruminants is very similar to that of other mammals, but the stomach is considerably different from the so-called "monogastric" condition.

The word "ruminant" comes from the Latin ruminare, to think; and as wildly laughable as the idea of a cow "thinking" may be, nevertheless, the contemplative and placid expression on a cow's face as she "chews her cud" does sort of give the impression that she's dealing with serious world problems.

You may have heard it said that cows have "four stomachs."

In an anatomic sense this is incorrect; there really is only one stomach, but it does have divisions.

The first three divisions of the ruminant stomach are sometimes considered to be diverticula of the esophagus; there is considerable debate on this point, however, and some authorities consider them derivatives of the stomach.

SYMBIOTIC RELATIONSHIPS
Symbiosis is a close ecological relationship between the individuals of two (or more) different species. Sometimes a symbiotic relationship benefits both species, sometimes one species benefits at the other's expense, and in other cases neither species benefits.

Ecologists use a different term for each type of symbiotic relationship:

Mutualism
-- both species benefit
Commensalism
-- one species benefits, the other is unaffected
Parasitism
-- one species benefits, the other is harmed
Competition
-- neither species benefits
Neutralism
-- both species are unaffected