A frightened armadillo leaps into the air at a Florida research station.
An armored invasion is underway across the midwestern and eastern United States: Armadillos are moving into new territories once thought unsuitable for the warm-weather creatures. There are 20 known species of armadillo, but only one—the nine-banded armadillo—has ventured out of Latin America. The species arrived in Texas during the 1880s and has been spreading into new habitats ever since.
In recent years the nine-banded armadillo has even established itself as far east as South Carolina and as far west as Illinois, and the animals are sometimes spotted in Indiana and Iowa. If the trend continues, some experts predict that the armadillo may soon be spotted in the wild as far north as Washington, D.C., or even New Jersey.
Some scientists have suggested that increasing temperatures due to climate change may be allowing armadillos to move into more habitats. But armadillo expert Colleen McDonough, a biologist at Valdosta State University in Georgia, doubts this is the case. For starters, armadillos have been consistently moving northward and eastward from the Rio Grande since the latter part of the 19th century, she said.
"There are different hypotheses as to why—one being that the expansion was facilitated by land-use practices and removal of large mammalian predators," she said. "Because this movement has been consistent over the years, I think it is a continuation
and not directly the result of recent climate change."
EDIT
http://news.nationalgeographic.com/news/2011/10/111007-armadillos-united-states-invasive-species-animals-environment/