A cute armadillo stands on its hind legs
A cute armadillo stands on its hind legs. (Photo: Ondrej Prosicky/Shutterstock)

How much do you really know about armadillos, beyond their leathery carapaces?

With 21 different species spread across the Americas, these "little armored ones" (as their name translates from Spanish) exhibit a wealth of diversity in size, behavior and environments. As distant relatives to other xenarthrans like tree sloths and anteaters, they boast some of the lowest basal metabolic rates of all mammals — a biological trait that has solidified them as a common carrier for the bacteria that causes leprosy, also known as Hansen's disease.

These creatures with the fascinating shells are more than meets the eye. Here are 13 fascinating facts you may not know about armadillos.

1. The nine-banded armadillo is the only species found in the U.S.

Nine-banded armadillo
(Photo: Heiko Kiera/Shutterstock)

Although all armadillo species originate from South America, only the nine-banded armadillo (Dasypus novemcinctus) has made it far enough north into the United States. If you happen to live in the South, it's not uncommon to find these critters rooting around in your backyard (or sadly, on the side of the road). This is especially true in hot, rainy environments like Texas, which named the nine-banded armadillo its state small mammal.

2. Brazilians love their Tolypeutes

An adorable baby tolypeutes
(Photo: belizar/Shutterstock)

As one of the most adorable Cingulata species out there, it's no wonder that the Brazilian three-banded armadillo (Tolypeutes tricinctus) was named the official mascot for the 2014 FIFA World Cup in Brazil. But that's not the only reason. After suffering a 30 percent decline in population over the past 10 years, this precious "tatu-bola" ("ball armadillo" in Portuguese) is now listed as vulnerable on the IUCN Red List due to rapid destruction of the creatures' natural habitats.

3. Giant glyptodonts are the extinct kin of today's armadillos

Glyptodonts
(Photo: Biodiversity Heritage Library/Herman Pijpers/Anne-Lise Heinrichs/Flickr)

When you think of extinct megafauna, the first creatures to pop into your head are usually dinosaurs or woolly mammoths, but there's a wealth of lesser-known, long-gone animals that are just as astounding. Glyptodonts, which evolved in South America during the Miocene (between 5 and 23 million years ago), were equipped with massive tortoise-like shells that made them comparable in size to small Volkswagen Beetles.

Like many other ancient megafauna, glyptodonts went extinct around the end of the last ice age, while their smaller and more lightly armored relatives survived.

4. Armadillos can sleep up to 19 hours a day

Sleepy armadillo
(Photo: MyImages - Micha/Shutterstock)

As nocturnal animals, armadillos perform most of the physical activities — foraging, eating, burrowing, mating — at night. This means that during the daylight hours (which can last a long time depending on the latitude and season), they spend their time snoozing in their burrows.

5. Yes, armadillos can spread leprosy, but there's more to that story

Southern Naked-tailed Armadillo in Pantanal, Brazil
(Photo: Ondrej Prosicky/Shutterstock)

It's no secret that armadillos are capable of contracting and passing along leprosy (as well as Chagas disease). Their low body temperature makes them perfect hosts for Mycobacterium leprae, so it is generally ill-advised to handle them or eat their meat. As a result, people are quick to recoil in their presence, but it's important to remember that humans are to blame for their condition.

Like many other infectious diseases, leprosy was brought to the New World by Europeans in the late 15th century, and it's widely accepted by zoologists that armadillos likely contracted leprosy from these newcomers. As a result, armadillos have become a natural reservoir for the disease.

6. Only two armadillo species are capable of rolling up into a ball

A rolled up armadillo
(Photo: belizar/Shutterstock)

Judging by the many cartoonish depictions of armadillos curling up into tight balls and rolling away, you'd assume that most species would be capable of this defense mechanism. But the only armadillos equipped with this adorable ability are the two species belonging to the Tolypeutes genus, also known as the Brazilian and southern three-banded armadillos. All other armadillo species have too many plates, making this kind of flexibility impossible.

7. The giant armadillo is the largest species

A giant armadillo captured in a camera trap
(Photo: Smithsonian's National Zoo/Flickr)

As the largest living armadillo species, Priodontes maximus typically weighs about 70 pounds, though they have reached a whopping 180 pounds in captivity.

Over the past 30 years, giant armadillos have experienced an estimated population decline of between 30 and 50 percent. As with many other armadillo species, one of the greatest threats to the giant armadillos is widespread habitat loss, though they are also vulnerable to hunting and black market trading.

8. The pink fairy armadillo is the smallest species

Pink fairy armadillo
(Photo: Cliff/Flickr)

In addition to its rosy-colored armor, the pink fairy armadillo (Chlamyphorus truncatus) is named for its diminutive size. Measuring between 3.5-4.5 inches in length, this creature typically weighs about 4.2 ounces.

The lovely species, which is found in the sandy plain and scrubby grasslands of central Argentina, is believed to be declining in population due to habitat loss and the predatory behavior of domestic cats and dogs, however the IUCN does not have enough data to assign a conservation status.

9. There's a reason this cutie is called a 'screaming hairy armadillo'

Screaming hairy armadillo
(Photo: Robert Eastman/Shutterstock)

You'd think an armored body would provide suitable protection against predators, but the screaming hairy armadillo (Chaetophractus vellerosus) is equipped with an even more robust insurance policy: A pair of screeching lungs. Anytime this species perceives a threat, it will emit extremely loud, alarm-like vocalizations.

10. The pichi is the only armadillo that hibernates

Pichi armadillo
(Photo: zixian/Shutterstock)

Armadillos spend the majority of their lives snoozing, but one species known as the pichi (Zaedyus pichiy) takes it a step further by hibernating every winter. After building up fat stores and settling down in a cozy burrow, the pichi's body temperature drops from 95 degrees Fahrenheit to a positively chilly 57 degrees.

11. Most armadillos are insectivorous, but some eat tiny animals

An armadillo rustles around the leaves for food.
(Photo: Jason Patrick Ross/Shutterstock)

While the vast majority of armadillos keep their dietary habits simple by digging and rooting in the ground for insects and worms, some individuals have been observed feasting on lizards, snakes, fowl eggs and fruit.

12. Armadillo shells were once used to make musical instruments

Charango made of an armadillo carapace
(Photo: LPLT/Wikimedia)

Known as charangos, these 10-stringed, lute-like instruments are an integral part of traditional Andean music in Bolivia, Chile, Ecuador and Peru. While they were once commonly made from the dried shell of an armadillo, contemporary incarnations of the charango are now made with wood or sometimes calabash gourds.

13. Armadillos love to have fun

While these peculiar creatures spend the majority of their time eating or sleeping, armadillos have also been known to get silly from time to time. In the video above, a southern three-banded armadillo named Rollie plays with a toy bear at a zoo in Green Bay, Wisconsin.

Catie Leary ( @catieleary ) writes about science, travel, animals and the arts.