The alarm call is a shrill whistle. It is most efficient for these small antelope to live in small groups with close social bonds and defend a specific home range. Migration would preclude intimate knowledge of food-plant locations and seasons. Since these antelope require specific types of plants, eating only easily digested young leaves, buds, fruit and flowers, keeping competition out of a home range ensures a more secure food supply. Small body size dictates a higher metabolic rate per kilogram of body weight.
Small herbivores have to take in more food per kilogram of body weight than larger animals.
Being ruminants, there is an additional constraint. The amount of food taken in at one time and the rate at which the food is processed in the rumen, balanced with a high metabolic rate, stipulates that the quality the food be very high. The antelope must choose their food very carefully. Being dry forest or desert animals, these diminutive antelope need a way to cool off. The enlarged proboscis is a cooling chamber in which the mucous membranes evaporative-cool the venous blood circulating through.