Psammomys – Sand rats

A small but remarkable group of desert-dwelling rodents found across North Africa and the Middle East. These little mammals may not look especially dramatic at first glance—they’re round-bodied, with sandy-colored fur, short tails, and small ears—but their story is all about survival in some of the harshest environments on Earth. Unlike many of their rodent cousins that thrive on seeds, grains, or insects, sand rats have evolved to live almost entirely on salty, low-energy desert plants, especially saltbush (Atriplex). This makes them some of the most extreme dietary specialists in the rodent world, turning them into true desert survivors.

Currently, the genus includes two species: the Fat sand rat (Psammomys obesus), which ranges widely across North Africa and parts of the Middle East, and the rarer Allenby’s sand rat (Psammomys vexillaris), found mainly in coastal areas of Israel, Egypt, and Libya. Both share the same chunky body shape and sand-colored camouflage, but the fat sand rat tends to be larger and bulkier, while Allenby’s sand rat is slightly smaller and slimmer. What unites them is their remarkable ability to thrive on salty shrubs that would be impossible food sources for most mammals. They rarely, if ever, need to drink water, as their efficient kidneys and digestive systems extract all the moisture they need from their food.

Sand rats also stand out because of their unusual connection to human health research. In captivity, when fed normal rodent diets of seeds, grains, or fruits, they quickly develop obesity and type 2 diabetes. Their bodies are so finely tuned to survive on nutrient-poor desert plants that richer foods overwhelm their metabolism. This makes them a natural model for studying diabetes in humans, and scientists have learned a great deal about metabolic disorders from these humble desert rodents. In the wild, though, they remain lean and healthy, perfectly adapted to their tough diets and desert lifestyles.