Many arid regions are now home to livestock such as cattle, sheep, and goats, as
well as those most famed of large desert-dwellers, the camels. Various
antelopes, gazelles, and ibex thrive on sparse grazing in semidesert regions of
Africa and Asia. Probably the best adapted for true desert life are the dama and
dorcas gazelles (Gazella dama and G. dorcas) of the Sahara. They are slender
and long-legged, pale fawn on the upper parts and white underneath, with Sshaped,
annular horns. They move with the rains to find the greenest vegetation,
eating grasses, herbs, and woody plants. In the breeding season each male
defends a patch of territory from other males and gathers a harem of females for
mating.
The pronghorn (Antilocarpa americana) of North American deserts is
sometimes called an “antelope,” but it is in fact more closely related to cattle
and deer. It has a small, forward-pointing branch, or “prong,” on each main horn
and horizontal dark and light stripes down its neck. It is one of the fastest of all
land animals, running at 65 kilometers per hour (40 mph), and is able to
maintain a speed of 40 to 50 kilometers per hour (25–30 mph) for many
minutes, enabling it to outpace most predators. It ranges across prairies and
semidesert, existing on tough vegetation and obtaining most of its water from its
food. Like most desert-dwellers, it produces concentrated urine, thereby losing
little body water.
In South America the main large herbivores are members of the camel group.
They include the guanaco (Lama guanicoe), which inhabits high regions of the
Patagonian Desert, and the vicuna (Vicugna vicugna) on the Andean mountain
edges of the Sechura and Atacama deserts. They resemble smaller, slimmer,
more dainty versions of their close and more familiar cousin, the llama. Indeed,
the guanaco is probably the wild ancestor of domesticated llamas and alpacas.
Both species feed on various forms of vegetation, especially grasses, and have
very long, woolly fur to keep out the mountain’s nighttime cold and daytime
heat.
The wild asses of Africa and Asia also wander in semidesert and rugged
country. They can withstand great heat and move nimbly among the rocks to
find food and shade. The African ass (Equus africanus), wild ancestor of the
domesticated ass, has suffered from military conflict through much of its range.