The
rule or
observation that the
skin of a
warm-blooded animal species tends to become
darker in color towards
warmer climates at lower
altitudes or lower
latitudes, and to become
lighter in color towards
colder climates at higher
altitudes or higher
latitudes.
From the BioTech Dictionary at http://biotech.icmb.utexas.edu/. For further information see the BioTech homenode.