… in the deserts of Argentina. Here dwells the remarkable pink fairy armadillo (Chlamyphorus truncatus), a 5-inch-long, quarter-pound critter with a rosy shell atop silky white hair. This smallest of all armadillos spends almost its entire life burrowing through the earth, hunting various invertebrates and chewing up plant matter. It is a rarely seen, almost totally unstudied marvel — what you read here is pretty much all we've observed about the pink fairy armadillo.
So exactly how elusive are they? Conservation biologist Mariella Superina of Argentina's National Scientific and Technical Research Council has been studying other armadillos in the pink fairy's habitat for 13 years and has never once seen one in the wild. And locals can't tell her how to track them. The only specimens she gets are injured ones found and brought in for rehabilitation or those confiscated from chuckleheads keeping them as pets.
Unlike in all other armadillos, the pink fairy's shell is not fully attached to its body, instead connecting with a membrane that runs along the spinal column. The thin carapace's underlying blood vessels actually show through, giving it that beautiful hue that you're now reconsidering being beautiful because it's made of blood.
The shell's fragility and flexibility suggest the creature doesn't rely on it as armor, as other armadillos clearly do. Instead, "it is well possible that it helps them thermoregulate, like a fennec fox's ears," Superina wrote in an email interview with WIRED, "as I've seen the carapace color change quite rapidly with changing environmental temperature, which was due to an increased (or reduced) irrigation in the blood vessels."
Exposing more blood to cool air or soil, for example, would lower the animal's body temperature, while draining the carapace would help it better retain heat. This would prove useful because the tiny pink fairy armadillo has a higher surface-area-to-volume ratio than a large critter, and will thus lose heat more rapidly. According to Bergmann's rule, this is why we tend to find — with some exceptions — larger creatures like polar bears in cold environments and smaller ones like pink fairy armadillos in deserts.