FRANKFORT, KY (12/8/11) - The nine-banded armadillo (Dasypus novemcinctus) has been expanding its range in the U.S. since the mid-1800s, steadily moving north and eastward.
Armadillos first appeared in western Kentucky more than 20 years ago. "I recall the first report was a road kill in Aurora," said Steve Bloemer, wildlife program manager at Land Between the Lakes National Recreation Area (LBL).
Bloemer has worked as a biologist since 1982 on this area, bordered by Kentucky Lake and Lake Barkley. Aurora, Kentucky lies at the western entrance to LBL on U.S. 68 in Marshall County.
"First there were reports from several counties in the region, then we started finding road kills in LBL and eventually we started seeing live armadillos here," said Bloemer.
The first confirmed sighting of a live armadillo in LBL was in the spring of 2002 when a farmer on a tractor saw one feeding at the edge of a field. Bloemer believes armadillos may have been present in the Tennessee River and Cumberland River bottoms for years before entering LBL.
"At first we were getting a disproportionate number of sightings on the north end of LBL, especially from campers driving in and out of the Hillman Ferry Campground," Bloemer explained.
The busy campground is just a few miles south of the Barkley Canal, which connects the two huge reservoirs near their dams. "This past summer we received a report from a bow fisherman who saw an armadillo swimming the Cumberland River," he said.
Rivers, lakes and small streams are not an obstacle to range expansion. James Loughry, a zoologist and armadillo expert at Valdosta State University in Georgia, said he believes armadillos move up watersheds. "It’s a misconception that they’re desert animals. Armadillos are more adapted to swamps and riparian areas where there’s wet soil."
Loughry said armadillos don’t swim well, but they gulp air to inflate their stomach and intestines, helping them float. "They can traverse smaller streams by sinking to the bottom and walking across to the other side," he said.
The mammals, which are primarily nocturnal, like to dig in loose soil, leaf litter and rotting logs looking for grubs, beetles, ants, termites and worms to eat. They lap up this prey with their sticky tongues. They also will eat amphibians, small reptiles, fungi and plant tubers.
Nine-banded armadillos typically weigh 12 to 22 pounds, with an overall length of 20 to 42 inches, including their tails. In the wild, they can live up to15 years and become sexually mature before they reach age two. Armadillos have a two to three month mating season in summer and a four-month gestation period. A single fertilized egg develops into four identical embryos. Young remain underground, living on mother’s milk for three months, before leaving their burrow.
The armadillo’s outer shell is made up of hardened bony plates covered with scales, which are connected by flexible bands of skin. This armor covers the back, sides, head, tail and outside surfaces of the legs. The underside of the body and the inner surfaces of the legs have no armored protection, but are covered by tough skin and a layer of coarse hair.
"The first road-killed armadillo I encountered in Kentucky was in 2003, and the first live one I saw was in 2006," said John MacGregor, a herpetologist with the Kentucky Department of Fish and Wildlife Resources.
MacGregor said in recent years there have been several confirmed sightings by staff biologists in eastern and south central Kentucky.
Steve Bonney, northeastern region wildlife coordinator for Kentucky Fish and Wildlife, encountered a road-killed armadillo in Rowan County in 2009 on the way to work. "I routinely record road kills. When I saw what I thought was an armadillo, my radar went off," said Bonney. "It kind of shocked me."
When Bonney arrived at work, he immediately drove back to the site of the road kill on Ky. 801 in Farmers, Kentucky to photograph and pick up the armadillo.
Of the 20 known species of armadillos, the nine-banded armadillo is the most widely distributed. It is the only armadillo species to have ventured north of Mexico. Today, the nine-banded armadillo is established as far east as South Carolina and as far west as southern Nebraska. Loughry said range expansion "has been consistent over the years, and is the continuation of a long-term trend."
But what biologists can’t agree on is why range expansion is occurring so fast. Factors that may be fueling this expansion include: climate change, the armadillo's general adaptability, its high reproductive rate and little desire on the part of humans to hunt or eat armadillos.
The two most likely things to cause armadillo mortality are getting run over by vehicles on roads or being eaten by coyotes.
"In the 1980s armadillos in Florida and Georgia merged with populations coming east from Texas, Louisiana and Mississippi," said Loughry.
Today, armadillos are established in 15 southeastern states. They are expanding into the Appalachians and up the Atlantic coast.
Information provided by Seth Stewart (KDFW)
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