Diet
Perhaps the most significant adaptation to desert gazelles is their diet. Gazelles are browsers, and will eat almost any vegetation available if the need is great enough -- from desert shrubs to rough desert grasses. They may also stand up on their hind legs to eat leaves from a variety of desert trees.
Blood Vessel Arrangement
Bodies are very sensitive to changes in internal temperature; there is even a certain threshold in which temperatures too high or low can cause brain damage and death. Desert gazelles have evolved a very special way of mitigating this problem. The blood vessels in their heads are arranged in a special order, so that the temperature of the brain can be as much as 5.5 degrees Fahrenheit lower than the body.
Low Moisture Needs
Most desert gazelles have adapted in such a way that they need very little water on a daily basis. In most cases, they get the moisture they need from the plants they eat. Most gazelles also feed primarily in the morning or evening, so that they can take advantage of any dew that has condensed on their forage.
Liver Protection
Many gazelle species have an unusual adaptation developed for desert living: they shrink their livers. This physiological ability allows gazelles to conserve water, and their livers may shrink by as much as 30 percent in especially dry seasons.