What does a kaenguru rat eat

Survive without drinking

The true thirst artists have made themselves completely free of the necessity of having to consume water in whatever form. They cover their needs almost exclusively through the H2O that occurs when the nutrients are burned - the so-called oxidation water.

The larva of the meal beetle Tenebrio, the so-called mealworm, is an example of this type of water extraction. Scientists have put his skills to the test: They only fed him anhydrous bran that had previously been dried at more than 100 degrees. They could not determine a decrease in the water content of the animal. How did it do that?

Burning fats is particularly effective when it comes to providing water. The oxidation of 100 grams of fat produces an amazing 107 grams of water. The processing of carbohydrates and proteins is much more modest with a water production of 55 and 43 grams respectively.

Kangaroo rat © U.S. Fish and Wildlife Service / George Harrison

Not only insects, but also some mammals use this mechanism to survive in the desert. Pocket jerboa, such as the kangaroo rat from the Dipodomys group, are at home in the arid regions of the New World. They are probably among the animals that are best adapted to the desert conditions.

In the wild, the small rodents feed exclusively on dry seeds. Researchers have now found that they never consume free drinking water. 90 percent of their needs come from oxidation water, the remaining ten percent provides the residual moisture in the food.

However, this principle only works because the kangaroo rat uses the water available to it very sparingly. For example, with the help of an extraordinarily efficient kidney, it produces very concentrated urine. In order to avoid water loss through sweating, she also spends large parts of the day deep underground in her cool burrow.

Status: February 24, 2005

February 24, 2005