Armadillos have been around for over 55 million years and have evolved excellent methods for protecting themselves. Unfortunately, automobiles have been around for a somewhat lesser period and evolution has not had time for these creatures to adapt. That's why they and, to a somewhat lesser extent, possums are our most commonly observed roadkill.
I suppose, if armadillos could fly, we'd be cleaning them off of our roofs because they'd be run over by airplanes. It's a toss-up as to who or what is the main predator of armadillos: carnivores like bears, bobcats, coyotes and dogs, or F-150 pick-up trucks. Probably the trucks.
The reason why we find armadillos dead along the side of the road is their instinctive reaction to danger. They do not curl themselves into balls. That's their cousin the three-banded armadillo that lives quite a few kilometers farther south. Instead, they reflexively leap straight up (as high as a meter) when startled. This action might scare off a potential predator, but F-150s don't seem to notice. In fact, instead of being run over by the vehicle's tires like most unfortunate victims of our highway system or having the vehicle pass harmlessly over them, they tend to be hit at the apogee of their jump by the car's bumper.
The nine-banded armadillo didn't always live in the U.S. Some time around the late 19th century, they crossed the Rio Grande into Texas and began their expansion north and east. One would think that a major tributary such as the Rio Grande would pose a significant barrier to the movement of such a relatively heavy animal. Because of their armor, you'd expect them to avoid water. It seems that armadillos have an ability to hold their breath for over 10 minutes and can cross a body of water by simply walking across the bottom. If a river is too wide, they can suck in enough air to inflate their lungs, stomach and intestines and can float across.
Seventy-five percent of their diet consists of insects (they're particularly fond of fire ants). Like their cousins the anteaters, armadillos have a long, sticky tongue. They can detect their prey as deep as 20 centimeters (8 inches) below ground. Besides insects, they will also eat birds, carrion, eggs, mice, reptiles and vegetation. They especially like melons, peanuts and tomatoes.
Armadillos prefer their habitat to have dense vegetation. The "digability" of soil is a major factor in determining the potential number of armadillos in a given area. Their range is limited by moisture and temperature. They can be found from Texas to Florida and north into central Arkansas. They don't hibernate and have to continuously forage for food throughout the year.
In warmer months, you're less likely to see a live armadillo. They spend the daylight hours sleeping in their burrow and come out only at night to search for food. As temperatures fall, their schedule reverses.
It's relatively easy to tell if an armadillo has been digging in your yard. They leave conical holes 2 to 5 centimeters (1 to 2 inches) deep. These are foraging pits. They also make a rather conspicuous trail. As they walk, they drag their tail, leaving a rope-like imprint between their footprints.
Controlling these creatures often will require the use of a professional. There are no poisons or repellants registered for use against armadillos. The only possible way of ridding your yard of armadillos is to trap them. They won't eat food off the surface of the ground, so there's no practical way to "bait" the trap.
To capture an armadillo, you have to find out where it lives or where it habitually walks. Once you've done this, you need to set up barriers to guide the animal into the trap. They have poor eyesight, so a set of boards or cinder blocks can be used to funnel the armadillo in the right direction. You might want to cover the bottom of the trap with dirt. Bare wires may alert the armadillo and keep it from going in.
Tim Lockley, a specialist in entomology, is retired from a 30-year career as a research scientist for the U.S. Department of Agriculture. For answers to individual questions, please send a stamped, self-addressed envelope to Tim Lockley, c/o Sun Herald, P.O. Box 4567, Biloxi MS 39535.