Pink Fairy Armadillo

The colour comes from the animal's own blood. Its dorsal shell, the armoured covering on its back, is much thinner and less heavily mineralised than the armour of other armadillos, thin enough that the network of small blood vessels in the tissue just beneath it shows through, tinting the pale shell a blush pink. There is evidence that the pink fairy armadillo can adjust how much blood flows to this shell, pumping more blood to it to release excess heat or restricting flow to conserve warmth, effectively using the shell as a temperature-regulating radiator, which would also cause its exact shade of pink to vary with the animal's condition and activity.

It is an exceptionally specialised burrower, with disproportionately large, powerful front claws and a body shape adapted for pushing through loose, sandy soil. Rather than digging an open tunnel the way many burrowing animals do, it essentially swims through the sand, using its claws to loosen material ahead and its body to compact it behind, so that the burrow largely collapses in its wake. If disturbed on the surface, it can dig itself completely out of sight in a matter of seconds, which is one reason it is so seldom seen even where it lives.

Almost every factor about the animal's lifestyle makes it hard to study. It is small, nocturnal, lives underground in a restricted region of central Argentina, and burrows out of sight almost instantly when disturbed, so field observations are extremely rare. It also does very poorly in captivity, with most individuals brought in by well-meaning people dying within days or weeks, apparently from stress, so it has not been possible to study it under controlled conditions either. As a result, basic questions about its lifespan, reproduction, population size, and even diet are still only partly answered, and the IUCN lists it as Data Deficient.

Its true conservation status is genuinely uncertain because so little is known about it, which is why it is officially classified as Data Deficient rather than being given a threat category. However, there is real concern among researchers, because its limited range of sandy grassland in central Argentina is increasingly being ploughed for agriculture, pesticides are reducing the ant and insect populations it feeds on, domestic dogs and cats kill individuals that surface, and animals are sometimes collected out of curiosity despite almost never surviving. Local reports suggest sightings have become less frequent over recent decades, which points toward a decline even in the absence of formal population data.