The fat sand rat (Psammomys obesus) is a terrestrial mammal from the gerbil subfamily that is mostly found in North Africa and the Middle East, Fat sand rats are very selective in their diet, only eating stems and leaves of plants from the family like the salty bush. In captivity, fat sand rats can become obese and rapidly develop diabetes-like symptoms when fed the diet typically given to other rodents, so they must be fed with salty food.