TheImprovement ofTropical and Subtropical Rangelands

250 IMPROVEMENT OF TROPIOAL AND SUBTROPIOAL RANGELANDS
able to keep up with the herd; a herder will often drop back to walk
with the mother and infant. Progrea is often slowed also by the need
to retrieve the animals that have wandered during the previous night
(during seasons when movement is infrequent, the trek animals are
collected and hobbled the day before, but when camp is being moved
each day, the animals must be left free to grue at night). A minor
factor affecting the speed with which the salt areas are attained is
the search for appropriate routes. Large lakes must be skirted, and in
the Sahara region good water and pasture again become a problem.
The northward journey, then, is not direct but carried out in a zigzag
fashion (figure 3-2).
During all seasons, the distance that a camp moves at anyone
time strictly depends on the availability of water and pasture, but
it normally ranges between 2 km and 30 km. Movement begins
at dawn (it takes approximately half an hour to break camp) and
continues only until noon. H still more territory needs to be covered,
the journey will resume after the day's heat diminishes.
During August and September, the movement pattern of alII",
both those who are a component of other camps and those who
are independent, is slightly different from that of the nobles and
mllrllbout8, since it is inftuenced by their search for wild grains. At
the time of the first harvest, iklan groups will converge upon the
areas that have been favored by rain or soil conditions. If the yield
is abundant, the second and third harvests will be limited to the
collection of grains encountered while herding; movements will be
less affected by the need to harvest.
A local variation of the general pattern of movement is found
among groups living near the Niger River, especially those between
Timbuktu and Gao. At the end of the hot season, and especially
if it is prolonged or severe, the groups will reverse their pattern of
fonowing the diminishing pasture away from the river and make a
forced march back toward it through now barren country in order to
feed their animals on the plant species, such as Echinocl&loa Itll,nina
(bur,u), exposed by the lowered water levels.
Movement of all groups is inftuenced by death and disease. N~
mads are aware of the danpr of contagion and will isolate the tent
of one who has an infectious illness. When traveling, they will try
to pass on the upwind side of a stricken camp. When a person dies,
he is buried several hundred meters from the camp, oriented to the
east in the Muslim fashion, and the grave is covered with straw, after