Goats indigenous to tropical and subtropical environments generally performed better than other ruminants in terms of survival, reproduction and expression of their genetic potential for growth and milk yield. Low body weight (BW) and low metabolic rates per BW0.75 allow desert goats to maintain a frugal energy and water economy. Some of the desert breeds, such as the Bedouin goats, are able to reduce their energy requirements by as much as 65 per cent in response to reduction in feed availability. The digestibility of dry matter and structural carbohydrates found in some breeds of desert goats fed on highly-lignified diets exceeds considerably that observed in non-desert goats and other domesticated ruminants. The capacity of goats to consume high-tannin browse and to detoxify the tannin is higher than that found in sheep and cattle under comparable conditions. These advantages are probably related to the ability of goats to control effectively their rumen environment. In addition, maintaining a steady pH in the rumen, and efficient recycling of key nutrients such as nitrogen and sulfur, enable goats to maintain a maximal ruminal fermentation rate at given conditions. In Mediterranean areas, goats exhibit a preference for browse available all year round even when plenty of green grass is available during spring. Adaptation to high-tannin feed is a long-time process that allows goats to benefit from a steady supply of forage.