Pink Fairies: The world’s smallest armadillo has a unique double skin

Of the twenty existing species of armadillos, there is one that stands out for countless reasons. Pink fairy armadillos are the world’s smallest armadillos, but the strangeness doesn’t end there. They have a pink color (unsurprisingly), enthusiastic shoots of fine white fur, and it was recently discovered that they have a trait never before seen in any other mammal.

“As strange as it may seem, the animal has a double layer of skin,” Cecilia Krmpototic, lead author of a new study published in the Journal Of Zoology, told LiveScience. “The outer layer, in which keratinized scales occur [in which dead tissue forms a thickened, protective layer] and osteoderms, acts as a mantle or covering over the inner layer, which exhibits abundant and fine white fur. This double skin is a unique feature among mammals.”

Their curious armor allows pink fairies to stay safe while burrowing underground, yet retain the flexibility to wander through tight holes. It’s a unique adaptation for a mammal, and it’s thought to have evolved when these armadillos made the switch 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, as they spend most of their time underground.

However, there are a lucky few, including Mariella Superina, chair of the IUCN SSC Anteater, Sloth and Armadillo Specialist Group, and an armadillo expert. Superina has come across live pink fairies during rescue work and we caught up with her to find out more about these unusual and elusive creatures.

a pink fairy armadillo digging

Pink fairy armadillos are adapted to an underground life and have impressive digging equipment.

Image courtesy of Guillermo Ferraris, provided by mariella superina

What are pink fairy armadillos like?

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

They dig underground, get into the basement of a road where they can’t dig any further, emerge and cross the road, and then people see them. The species is so unusual that people sometimes round them up and take them to environmental authorities just because they are so rarely seen.

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

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

The juveniles usually weigh about 70 to 80 grams [2.5 to 2.8 ounces] and fits in the palm of your hand. The silky white fur is very soft and compared to other armadillos their back armor is extremely flexible and delicate. They can scream when they are scared, which is what the workers in a vineyard heard while digging a hole – they had accidentally injured a PFA that was foraging for the insects around the roots of the vines. We took x-rays and CT scans of that person, but unfortunately were unable to save them.

a pink fairy armadillo

One of the injured pink fairy armadillos being cared for by Superina’s team.

Image courtesy of Guillermo Ferraris, provided by Mariella Superina

What adaptations do pink fairy armadillos have?

MRS: They are fully adapted to life underground – which are not the same traits you need to survive above ground. For example, they walk on the tips of their long front claws and their hind legs are turned inwards – the position of the hind legs gives them more stability when digging with the long front claws, but is not very practical when walking.

They stagger while walking above ground, which makes them look rather clumsy and cannot walk very fast. Usually they only walk a few meters above the ground and then dig back into the sand.

They are very vulnerable animals that usually do not survive longer than eight days under human care. We don’t yet know why that is the case; they are certainly sensitive to sudden temperature changes, but are also very picky eaters.

I once kept an individual in human care for eight months and tried a wide variety of ingredients until I finally found a diet that the animal would accept. The next person I received for rehabilitation did not follow that diet… So it seems they also have strong individual preferences for their food.

Do you have a favorite fact about pink fairy armadillos?

MRS: Oh, I have a lot of favorite facts about them! For example, Christofredo Jakob, a neuroscientist, studied PFAs in the 1940s. He discovered that their extraordinary sense of smell is reflected in a huge olfactory brain, which makes up almost two-thirds of their brain. By comparison, humans’ olfactory brain represents only 2 percent of the brain. As a result, the sense of smell of PFAs is at least 100 times stronger than that of primates.

The fact that they use their shell for thermoregulation is also amazing; the color of the shell changes from light pink when it is cold to intense pink when it is warm.

The tip of the tail is diamond-shaped and the PFA uses it as a “fifth leg” when standing on its hind legs. It forms a kind of tripod, which provides good stability and frees the front legs so that he can dig.

Video courtesy of Mariella Superina

The way they fill their tunnels is also very cool. We actually found out when a colleague contacted me because he couldn’t identify some fossilized burrows but thought PFAs could have dug them. I just kept that PFA for eight months and had infrared cameras with motion sensors installed. 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?

MRS: I have spoken to many locals who have lived in the Mendoza desert all their lives, and those who have seen a PFA remembered that encounter very clearly. For example, a woman who lived on a desert ranch for more than 80 years 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 as she remembered these unique moments.

Some say it’s a privilege to encounter a PFA in the wild. Isn’t it amazing that there is a small animal out there that is so rarely seen, cannot be tracked by locals and cannot be caught using traditional methods?

pink fairy armadillo habitat

A pink fairy armadillo habitat.

Image courtesy of Guillermo Ferraris, provided by Mariella Superina

Is studying and caring for pink fairy armadillos difficult?

MRS: This was a huge challenge. For starters, we didn’t know how to keep them alive under human care. Previous experiences of researchers and locals keeping them illegally indicated that they would not survive 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 sufficient consistency (loose sand doesn’t work, because they can’t dig a stable burrow in it).

Then the diet. We collected wild fruits and insects in the desert, tried all the different ingredients I usually use to rehabilitate other armadillo species, even my ‘secret recipes’ that even the weakest armadillos would eat – the PFA just wouldn’t accept anything. Furthermore, as desert animals they do not drink water, so the diet had to be the right consistency to ensure they get enough fluid.

But there’s more! They are very delicate, as mentioned above. When the little PFA I kept for eight months came out in the evening and the sign wasn’t ready, it would run around like crazy. So we had to respect the feeding times. Our lives were basically dominated by an 80-gram [3-ounce] animal.

There were of course more challenges, some of which we have not yet solved. We didn’t know how to sedate them and couldn’t (and still don’t) take a blood sample for basic analyses. But with every PFA rescued, we learn a little more about this amazing little creature!

What makes them so special to you?

MRS: They are unusual. Different. Unique. They are a mystery to science because they are so difficult to study. Researching any species of armadillo is a challenge, but this tiny species challenges us even more. But that’s exactly the fun of researching armadillos and PFAs!

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