 The Desert Locust is a type of grasshopper that lives in the deserts of Africa, the Middle East and Southwest Asia, where there is very little rainfall, less than 200 mm a year. Desert Locusts are different from grasshoppers because they form giant swarms. A swarm of one square kilometer can contain up to 80 million locusts and eat the same amount of food in a day as 35,000 people. This is why the Desert Locust is a world's most dangerous migratory pest. A locust lives for about three months. After good rains in the desert, the sand becomes wet and green vegetation appears. Locusts begin to gather and mature. Females lay eggs that hatch after two weeks into young wingless hoppers, which become adults after six weeks. One month later, the adults are ready to lay eggs again. If ecological conditions remain favorable, locusts will breed again and this time they will change from an unremarkable solitary insect into a highly mobile, voracious swarm that devours crops in pastureland at an astonishing rate. Normally, Desert Locusts blend in with the deserts. The hoppers are green like the vegetation and the adults are brown like the sand. But their colors change when they increase in number. Young wingless hoppers turn to black and yellow to form bands. Adults become bright pink or yellow to form swarms. When the vegetation dries out, the swarms will migrate up to 150 kilometers during the day to greener places. They can invade countries where they are not usually found and they can cross oceans. Desert locusts do not attack people or animals. They do not carry diseases that are harmful to animals. But they do eat massive quantities of vegetation, while plants, bushes, crops and grass that are critical for the health and survival of millions of farmers and pastoralists. So locusts effectively steal food from people's mouths and from livestock. They leave people and animals hungry and households without milk or grain. When locust swarms become very big, the only way to reduce their numbers is by aerial spraying. If the swarms are not controlled, they can spiral into a plague and impact as many as 60 countries, affecting the livelihoods of 10% of the world's population.