Ever since the nine-banded armadillo was first sighted in Texas -- coming in from Mexico -- they have been growing in population ever since. Although most prevalent in the Southwest, states like Colorado, Utah and Illinois have had sightings and researchers are speculating that areas like the District of Columbia and New Jersey could expect to see them in coming years as well.
National Geographic reports this trend has been used to show support for global climate change but armadillo experts say this isn't the case:
"There are different hypotheses as to why—one being that the expansion was facilitated by land-use practices and removal of large mammalian predators," said Colleen McDonough, a biologist and armadillo expert at Valdosta State University in Georgia.
"Because this movement has been consistent over the years, I think it is a continuation [of a longer-term trend] and not directly the result of recent climate change."
In terms of how armadillos will affect their new environment, aside from drawing stares from northerners not used to seeing the strange, armored, placental mammal in their neck of the woods, they will compete with other wildlife, among other effects. National Geographic has more:
The mammals are known to dig up insect larvae for food, and it's possible they will compete for such meals with resident animals such as skunks. Armadillos have also been known to raid the nests of various species and so could harm populations of ground-nesting birds such as quail.
While searching for insects and the like, armadillos have been known to destroy lawns and gardens, to the dismay of homeowners. But insects and bird eggs are not the only thing armadillos eat. They are also known to eat carrion -- frequently in the form of roadkill -- which often makes them roadkill as well. Southeastern and westerns are all to familiar with armadillo roadkill.
Although these invaders are highly adaptable and strong breeders -- females can bear young after at a year old -- they won't expand into extreme northern climates due to cold weather. Armadillos do not store much body fat and do not hibernate, meaning they continue to forage year round.