Addax barely ever drink water. They get almost all the moisture they need from the plants they eat. They can sniff out the smell of dry grasses from kilometres away - and they walk towards rain clouds when they see them, knowing fresh grass will pop up soon after a desert shower.
Their wide, flat hooves spread out across soft sand the same way camels' do, so they don't sink. They are also brilliant runners - they can sprint at 70 km/h across the dunes when they need to escape from danger.
Both male and female addax grow long curling horns that twist into a spiral - up to 90 cm long. Up close, you can count the rings on the horns to work out roughly how old the antelope is, the same way you can count rings inside a tree.
There are sadly only a few hundred addax left in the wild. Algeria, Niger and Chad share the last wild population. Scientists in zoos around the world are breeding more addax and very slowly releasing them back into the Sahara. The hope is that one day there will be big herds again.