Armadillos are among the most distinctive-looking of all mammals. They look a bit like a cross between a polecat and an armored dinosaur. But what is an armadillo related to? You might be surprised to learn that these animals have some unexpected cousins in the animal kingdom.
Armadillos Belong to the Superorder Xenarthra
Armadillos are classified in the order Cingulata, which means “belted” in Latin. This refers to the bony plates that cover the back, head, legs, and tail of most of these odd-looking creatures. Armadillos are the only living mammals that wear such shells.
Cingulata is one of the two orders that make up the superorder Xenarthra, which means “strange joints” in Greek. This name reflects the fact that these animals have extra articulations in their vertebrae, which give them more flexibility and strength.
The other order in Xenarthra is Pilosa, which includes sloths and anteaters. These animals may not look much like armadillos, but they share some common features, such as long claws, reduced teeth, and a low metabolic rate.
Xenarthra is one of the four major groups of placental mammals, along with Afrotheria, Laurasiatheria, and Euarchontoglires. These groups diverged from each other about 100 million years ago, during the Cretaceous period.
Armadillos Are Native to the Americas
Armadillos originated in South America millions of years ago, when this continent was isolated from the rest of the world. They evolved from a group of extinct mammals called palaeanodonts, which were also related to sloths and anteaters.
About three million years ago, the formation of the Isthmus of Panama connected South America with North America, allowing an exchange of fauna between the two continents. This event is known as the Great American Interchange.
Some armadillo species migrated northward and colonized new habitats, while other types of mammals moved southward and replaced some of the native South American fauna.
Today, there are 21 recognized species of armadillo, ranging in size from the 5-inch-long pink fairy armadillo to the 5-foot-long giant armadillo. All of them are still present in South America, but only one species, the nine-banded armadillo, has expanded its range to Central and North America.
Armadillos Have Unique Adaptations and Behaviors
Armadillos have evolved various adaptations and behaviors to survive in their environments. For example:
- Armadillos have a keen sense of smell and long tongues that help them find and eat insects, their main food source. They also eat small vertebrates, plants, fruits, and carrion.
- Armadillos have strong legs and claws that allow them to dig burrows for shelter and escape from predators. Some species can also swim or jump to avoid danger.
- Armadillos have low body temperatures and lack fat stores, making them vulnerable to cold weather. They sleep for up to 16 hours a day to conserve energy and forage in the early morning and evening.
- Armadillos have poor eyesight and hearing, but they can communicate with each other through sounds and scents. They can produce grunts, squeaks, hisses, and snorts to express their emotions or warn others of threats.
- Armadillos have a remarkable reproductive strategy: they can delay implantation of fertilized eggs for several months until environmental conditions are favorable. They also give birth to identical quadruplets from a single egg.
Armadillos Are Fascinating but Threatened Animals
Armadillos are fascinating animals that have intrigued scientists and naturalists for centuries. Charles Darwin was one of the first to study them and collect their fossils during his voyage on the HMS Beagle.
Armadillos are also important for ecological and medical research. They play a role in controlling insect pests and dispersing seeds. They are also one of the few animals that can contract leprosy, making them valuable for studying this disease.
However, armadillos face many threats from human activities, such as habitat loss, hunting, roadkill, and climate change. Some species are endangered or vulnerable to extinction.
Therefore, it is important to protect and conserve these amazing animals and their habitats. By doing so, we can also preserve their evolutionary history and their role in nature.