Why do desert rodents have long loops of Henle?

Desert rodents possess long loops of Henle to maximize the recovery of water and sodium chloride from urine.1

The primary function of the loop of Henle is to create a concentrated environment within the kidney by actively transporting solutes into the surrounding tissue. By having a longer loop, these animals can establish a steeper concentration gradient, which allows for the production of urine that is significantly more concentrated than their blood plasma. This physiological adaptation is crucial for survival in arid environments, as it minimizes the amount of water lost through excretion, thereby reducing the animal's overall water intake requirements.12