"He that has satisfied his thirst turns his back on the well." -Baltazar Gracian
A Kangaroo Rat, note the large hind limbs.
Kangaroo Rats are an interesting little desert rodent, with a variety of adaptations to desert living. Perhaps the most readily observable is their morphology (body shape) and their method of locomotion. These animals have large, powerful hind limbs. Just like the Collared Lizards we previously discussed Kangaroo Rats never miss leg day at the gym. They exploit bipedal motion just like the Collared Lizard. Although rather than bipedal running the Kangaroo Rats tend to hop, like their Aussie namesakes. They leap about 1-2 feet per hop when they are in a hurry. No small feat for a small animal such as this. These powerful hind limbs also allow them display impressive vertical leaps when frightened or threatened by a predator. One kangaroo rat was observed to jump 5 feet horizontally and over 2 feet vertically. Based on their body size this is the equivalent of a six foot human leaping 60 feet on the long jump while simultaneously reaching 24 feet vertically. Now that's a leap!
Kangaroo Rats also have some pretty awesome adaptations to live in desert environments. They have very low metabolic rates and a low thermal conductance compared to a closely related species found in wetter environments. This helps them thermoregulate and minimize water loss. This might indicate that their adaptations to desert life happened relative late in their evolutionary history. Which makes sense because North American deserts haven't been around for very long relatively speaking.
Perhaps most amazingly is that the Kangaroo Rats REFUSE to drink, even when water is available to them. Seems counter-intuitive considering they live in some of the driest areas in the world. How can Kangaroo Rats do this without succumbing to their harsh environment?
Kangaroo rats gather dry seeds and then bring them back to their burrow to store and consume them later. Their burrows are much more humid than the outside environment, and that atmospheric water moves into the stored seeds. When the Kangaroo Rats eat the seeds they are full of water from their humid burrows. The behavior and physiology of the Kangaroo Rat complement each other in such way that help it easily survive in the desert, even without drinking a drop of water in their lives.
References and further reading:
Schmidt‐Nielsen, Bodil, and Knut Schmidt‐Nielsen. "A complete account of the water metabolism in kangaroo rats and an experimental verification." Journal of Cellular and Comparative Physiology 38.2 (1951): 165-181.
Bartholomew, George A., and Herbert H. Caswell. "Locomotion in kangaroo rats and its adaptive significance." Journal of Mammalogy (1951): 155-169.
McNab, Brian K. "Climatic adaptation in the energetics of heteromyid rodents."Comparative Biochemistry and Physiology Part A: Physiology 62.4 (1979): 813-820.