What curious creature with its own built-in armor digs its way into trouble but floats right out?
The armadillo!
Armadillos are a fascinating family of mammals. Originating in South America, all armadillo subspecies still dwell there, but a few have made their way to Central and North America as well. Today let’s focus on one type, the nine-banded armadillo, who ranges the farthest and is the only armadillo species found in the United States.
While armadillo ancestors evolved in South America during a period of continental isolation, some members made their way north in the Great American Interchange during the late Cenozoic period, when the creation of the isthmus of Panama allowed fauna to migrate between South and Central America. In what must have been a fascinating time of biological exchange, armadillos, among others, made the crossing north, resulting in the unlikely success story of the nine-banded armadillo that we see today.
(Photo by David Cutts of Cutts Nature Photography)
Armored and ready for action
The name “armadillo” translates to “little armored one” in Spanish, referencing the bony plates that protect their body. Contrary to popular belief, nine-banded armadillos cannot roll up into spherical balls like their three-banded relatives. And despite the name, these armadillos don’t always have 9 bands, but instead typically sport anywhere from 7 to 11 bands on their armor.
They thrive in warm, wet climates and tend to inhabit forested or grassland habitats. These mammals are not deterred by small streams and bodies of water, as they can hold their breath for up to six minutes and traverse rivers either by swimming or walking along the riverbed. They can even inflate their intestines to help them float across the water’s surface. Talk about resourcefulness!
These armadillos are also excellent diggers, with long claws they use to create underground homes or scavenge the soil for grubs. The burrows they create, once abandoned, can become homes for various other animals, including snakes, rabbits, opossums, and owls. And while humans tend to view the armadillos’ digging habits as a nuisance, disturbing lawns or agricultural lands, many other animals take advantage of the turnover that the armadillo creates as they pursue their own quests for food and shelter.
As generalist feeders, nine-banded armadillos have an impressive sense of smell, enabling them to locate a wide range of food sources. Given that they have relatively poor eyesight, it pays to rely on olfactory senses instead. They primarily consume invertebrates such as beetles, cockroaches, ants, and spiders.
By targeting insect populations, nine-banded armadillos help regulate their numbers, maintaining balance within ecosystems. Small reptiles, amphibians, and eggs of mammals, reptiles, and birds also make up a portion of their diet. And although it is less common (just 10% of their diet compared to animal matter), nine-banded armadillos can supplement their nutrition with fruits, seeds, fungi, and other plant matter.
Remarkable Reproduction
In human reproduction, we tend to think of the birth of twins as a rare and special occurrence, triplets as an even more amazing feat, and quadruplets as nothing short of a miracle. But it turns out that for nine-banded armadillos, having identical quadruplets is completely normal, and what you would expect from a pregnant mother.
This strange phenomenon, known as obligate polyembryony (when two or more embryos develop from a single fertilized egg), means that armadillo mothers carry litters of four identical offspring that have split from the same fertilized egg and are nurtured in the same placenta. Armadillos tend to breed in late July, after which the embryos are kept in a dormant state until November, and gestate for five months until their birth in March.
(Photo by Bianca Lavies from National Geographic)
The offspring are born with soft carapaces (or upper shells) and are highly vulnerable to predation until their armor hardens. The protective armor serves as a defense against predators like mountain lions, black bears, and alligators. These armadillos are nocturnal creatures, spending their active hours either burrowing or foraging for food.
It’s hard to make a habitat a home
Armadillo of Central and North America tend to have less genetic diversity and specialization than their South American relatives, but due to an absence of natural predators, over time they have been able to consistently expand their range. Nine-banded armadillos are predominantly concentrated in the Southeastern US, but have been seen as far north as southern Nebraska, southern Illinois, and southern Indiana.
In fact, it’s thought that the nine-banded armadillo still has more roving to do to reach the extent of its potential range, which may extend through Northern Massachusetts and beyond as climate conditions change. So depending on where you are, you might have a chance to see some cute new critters in the neighborhood soon!
Unfortunately, these creatures are not always welcomed with open arms. Nine-banded armadillos have been the victims not only of accidental vehicle collisions on roadways, but have to contend with hunting, poaching, and “pest control”. Some who perceive them as pests resort to poisoning, shooting, or capturing them. It can be a tricky thing to change hard-hearted attitudes, but armadillos are designated as the state of Texas’s official small mammal, and hopefully taking some point of pride or interest in these creatures can extend our compassion for them.
Despite the challenges they face, the nine-banded armadillo population is generally the subject of much less concern than the populations and livelihoods of some of their cousins in South America, which face severe threat from deforestation and habitat destruction. Conservation measures, including championing agroforestry and other alternatives to forest decimation and monocropping that can alleviate economic pressures while protecting biodiversity, continue to be essential for the longevity of wildlife. The only truly sustainable way forward on this planet involves valuing the complexity and diversity of living systems as foundational to the wellbeing of all.
The nine-banded armadillo and its variety of relatives demonstrate remarkable adaptability and survival skills. Their distinct armor and ability to thrive in diverse habitats offer an example of what it takes to succeed over time on a changing Earth. As we continue to learn about and appreciate these captivating creatures, it is crucial to ensure their conservation and coexistence with humans, allowing them to thrive as they float, swim, and scurry through our lives.
Here’s to resilience in its many forms,
Maya
Maya Dutta is an environmental advocate and ecosystem restorer working to spread understanding on the key role of biodiversity in shaping the climate and the water, carbon, nutrient and energy cycles we rely on. She is passionate about climate change adaptation and mitigation and the ways that community-led ecosystem restoration can fight global climate change while improving the livelihood and equity of human communities. Having grown up in New York City and lived in cities all her life, Maya is interested in creating more natural infrastructure, biodiversity, and access to nature and ecological connection in urban areas.
Sources:
https://www.nwf.org/Educational-Resources/Wildlife-Guide/Mammals/Nine-Banded-Armadillo
https://www.treehugger.com/things-you-didnt-know-about-armadillos-4869732
https://edis.ifas.ufl.edu/publication/UW082
https://tpwd.texas.gov/huntwild/wild/species/dillo/
https://en.wikipedia.org/wiki/Nine-banded_armadillo
https://en.wikipedia.org/wiki/Great_American_Interchange
https://animaldiversity.org/accounts/Dasypus_novemcinctus/