Pink Fairies: The World’s Smallest Armadillo Has A Unique Double Skin

Of the 20 extant species of armadillo, there is one that stands out for a myriad of reasons. Pink fairy armadillos are the world’s smallest armadillos, but the weirdness doesn’t stop there. They have pink coloration (unsurprisingly), enthusiastic sprouts of fine white fur, and recently it was discovered that they have a trait that’s never been seen in any other mammal before.

“As strange as it may seem, the animal possesses a double layer of skin,” said Cecilia Krmpotic, lead author of a new study published in the Journal Of Zoology, to Live Science. “The outermost layer, housing cornified scales [in which dead tissue forms a thickened, protective layer] and osteoderms, acts as a mantle or covering over the inner layer, which displays an abundant and fine white fur. This double skin is a unique feature among mammals.”

Their curious armor means pink fairies can stay safe while burrowing underground, but maintain the flexibility to noodle through narrow gaps. It’s a unique adaptation for a mammal, and one that’s thought to have emerged when these armadillos made the move from a terrestrial to a subterranean way of life, which occurred between 32 and 17 million years ago. For this reason, very few people have seen a living pink fairy armadillo because they spend most of their time underground.

There are a lucky few, however, one of whom is Mariella Superina, chair of the IUCN SSC Anteater, Sloth and Armadillo Specialist Group, and an armadillo expert. Superina has encountered living pink fairies during rescue work, and we caught up with her to find out more about these unusual and elusive critters. 

Pink fairy armadillos are adapted to a subterranean life and have impressive burrowing equipment.
Image courtesy of Guillermo Ferraris, provided by mariella superina

What are pink fairy armadillos like?

Mariella Superina: The majority of pink fairy armadillos (PFAs) we’ve rescued were juvenile males found on a road, trail, or in the middle of a village in February or March. We suspect that this is the time that the young – and, apparently, chiefly the males – have to leave their mother’s territory. 

They dig underground, hit the basement of a road where they can’t continue digging, emerge to cross the road, and that’s when people see them. The species is so unusual that sometimes people pick them up and take them to the environmental authorities just because they are so rarely seen. 

I remember one case where a person saw one crossing a road, picked it up to help it get to the other side of the road, but apparently, the PFA wanted to go the other way… It turned around and walked over the road again. The guy put it in a bucket and drove it about 200 kilometers [124 miles] to the nearest city to hand it over to the authorities – which then had to drive 200 km back to release it.

Another rescue was seen by the police in a small village, near a road. They called the authorities, which then called us. We drove about 150 km [93 miles] to evaluate the animal. As it was healthy, we immediately released it in a safe place.

The juveniles usually weigh around 70 to 80 grams [2.5 to 2.8 ounces] and fit in the palm of your hand. The silky white fur is very soft, and compared to other armadillos, their dorsal armor is extremely flexible and delicate. They can scream when frightened, which is what workers in a vineyard heard when they were digging a hole – they had accidentally injured a PFA that was foraging on the insects around the roots of the vines. We took X-rays and CT scans of that individual, but unfortunately couldn’t save it.

One of the injured pink fairy armadillos cared for by Superina’s team.
Image courtesy of Guillermo Ferraris, provided by Mariella Superina

What adaptations do pink fairy armadillos have?

MS: They are completely adapted to living underground – which are not the same characteristics you need to survive aboveground. So, for instance, they walk on the tips of the long foreclaws, and their hindlegs are turned inwards – the position of the hindlegs gives them more stability while digging with the long foreclaws, but are not very practical when walking. 

They waddle while walking aboveground, so they look quite clumsy and are not able to walk very fast. Usually, they’ll only walk a couple of meters aboveground, then dig into the sand again.

They’re very delicate animals that usually don’t survive for more than eight days under human care. We don’t know yet why that is so; they are certainly susceptible to sudden temperature changes but are also very picky eaters. 

I once kept an individual under human care for eight months and tried a wide range of ingredients until I finally found a diet the animal would accept. The next individual I received for rehab did not eat that diet… So, it looks like they also have strong individual preferences for their food.

Do you have a favorite fact about pink fairy armadillos?

MS: Oh, I have lots of favorite facts about them! For instance, Christofredo Jakob, a neuroscientist, studied PFAs in the 1940s. He found out that their extraordinary sense of smell is reflected in a huge olfactory brain, which accounts for almost two-thirds of their brain. As a comparison, the olfactory brain of humans only represents 2 percent of the brain. As a consequence, the sense of smell of PFAs is at least 100 times stronger than that of primates.

The fact that they use their carapace for thermoregulation is also amazing; the carapace color changes from a pale pink when it’s cold, to an intense pink when it’s hot.

The tip of the tail is diamond-shaped, and the PFA uses it as a “fifth leg” when standing on its hindfeet. It forms sort of a tripod, which provides good stability and frees up the forelegs that it can then use to dig.

          
Video courtesy of Mariella Superina

Also, the way they backfill their tunnels is very cool. We actually found out about it when a colleague contacted me because he couldn’t identify some fossilized burrows, but thought that PFAs could have dug them. I was just keeping that PFA for eight months and had installed infrared cameras with motion sensors. We compared the pattern left by “my” PFA with the fossilized burrows, and it was a match!

How rare is it to spot a pink fairy armadillo in the wild?

MS: I’ve talked to many locals who have lived their entire life in the desert of Mendoza, and those who’ve seen a PFA remembered that encounter very well. For instance, one woman who lived over 80 years on a farm in the desert told me that she had seen three PFAs in her entire life. When she told me about these little animals, her face lit up and she smiled, remembering these unique moments. 

Some say it’s a privilege to encounter a PFA in the wild. Isn’t it amazing that there’s a tiny little animal out there that is so rarely seen, can’t be tracked by the locals, and can’t be trapped with traditional methods?

A pink fairy armadillo habitat.
Image courtesy of Guillermo Ferraris, provided by Mariella Superina

Is studying and caring for pink fairy armadillos difficult?

MS: This was a huge challenge. To start with, we didn’t know how to keep them alive under human care. Previous experiences by researchers and locals who kept them illegally indicated that they would not survive for more than eight days, but we did not know why. We knew they needed a sandy substrate, but only after several attempts did we find the adequate consistency (loose sand doesn’t work, as they can’t dig a stable burrow in it). 

Then, the diet. We collected wild fruit and insects in the desert, tried all the different ingredients I usually use to rehab other armadillo species, even my “secret recipes” that even the weakest armadillos would eat – the PFA just wouldn’t accept anything. Plus, as desert animals, they don’t drink water, so the diet had to have the appropriate consistency to ensure they’d ingest enough fluids. 

But there’s more! They are really delicate, as mentioned above. If the little PFA I kept for eight months emerged in the evening and its food plate was not ready, it would run around like crazy. So, we had to respect its feeding times. Our life was basically dominated by an 80-gram [3-ounce] animal.

There were, of course, additional challenges, some of which we haven’t solved yet. We didn’t know how to anesthetize them and had (and still have) no way of collecting a blood sample for basic analyses. But with each rescued PFA, we’re learning a bit more about this amazing little creature!

What makes them so special to you?

MS: They are unusual. Different. Unique. They’re a mystery to science because it’s so difficult to study them. Doing research on any armadillo species is challenging, but this little species challenges us even more. But that’s exactly the fun of doing research on armadillos, and on PFAs!

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