Addax are sometimes called the 'desert ghost' because they wander huge distances, following rare rains across the Sahara. They can sense when rain has fallen far away and travel towards it to reach freshly sprouted grass. Scientists are not entirely sure how they do this - it may be smell, or changes in the air.
Like the fennec fox, the addax can live without drinking water for long periods, getting moisture from the plants it eats. Its kidneys are very efficient at saving water inside the body. Its white-and-sandy coat helps reflect heat in summer; in winter the coat grows darker to absorb warmth from the sun.
Addax move in small herds and use their broad, shovel-like hooves to walk on soft sand without sinking. Compared to thinner-hooved animals, they move through desert sand the way snowshoes help people walk on snow.
There are sadly very few addax left in the wild today - perhaps only a handful in the whole Sahara. But conservation projects in Mauritania and neighbouring countries are working to protect and increase their numbers, and some addax have been bred safely in special reserves and reintroduced.