Armadillos

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Published on: Mar. 2, 1997

Last revision: Oct. 26, 2010

What I see has to be science fiction straight out of an artist's imagination. "I'll draw a creature born with armor," says the artist. "That's cool. Long snout, small mouth, bumpy tongue covered with sticky saliva. Tapering tail with ever decreasing armor rings. More detail - hair sticking out between the chinks in the carapace and below it. What else? Aha! Long, sharp claws!" The artist draws it springing into the air, claws spread.

But the creature I'm approaching is real, a living work of nature's art, and it's no threat to me, though it might jump three or four feet straight up if startled. The size of an extra-large house cat, it's oblivious to my presence. All it wants to do with those claws is dig for the insects its sensitive, snuffling nose detects underground.

This timid mammal in search of food at the Drury-Mincy Conservation Area in Taney County is Dasypus novemcinctus, the nine-banded armadillo, a k a the common long-nosed armadillo. Novemcinctus refers to the nine narrow plates that allow flexibility in its midsection.

Since 1980, the nine-banded armadillo has made itself at home in Missouri, moving northward to and even across the Missouri River, according to a 1994 report by Kimberley Lippert Mackey and Paul T. Schell, then graduate students at Southwest Missouri State University, Springfield. Survey respondents in areas around Cassville, Roaring River State Park and West Plains reported the most sightings. (Conservationist readers participated in the survey.)

Armadillo, meaning "little armored one," was the name the Spanish gave shell-wearing mammals they encountered in the New World. Armadillos exist only in the Americas, with South America home to all 20 species. Two of those, the nine-banded and the northern naked-tail armadillo, also live in Central America and Mexico.

Only the nine-banded migrated into this country. First recorded in Texas in 1849, it expanded its range north and east, at times aided by pranksters and animal dealers. In Florida, releases from a zoo in 1924 and a circus truck in 1936 started another migrating population. Now the northern edge of armadillo territory runs through Kansas, Missouri, Tennessee, Alabama, Georgia and South Carolina. Though this expansion has taken almost 150 years, that's fast for a mammal.

It isn't the first armadillo to live here. A similar but larger armadillo lived in what is now Missouri during the Pleistocene (a geologic epoch). It disappeared at the end of the last ice age.

Armadillos have inspired curiosity in people first meeting the "little armored one" and frustration in those dealing with the "little lawn-and-garden tiller." It can smell beetles, larvae and ants six inches underground, and it spends its waking hours eating them. It digs, pushes its nose into loosened soil, shoots out its sticky tongue to collect a meal and immediately digs another hole. Since its tongue is not selective, the feast includes an occasional earthworm, snake or skink, as well as rocks and earth. The armadillo's scat, understandably, resembles clay marbles.

If you're facing torn-up turf, it's small consolation the nine-banded trundled into Missouri and not the 130-pound giant armadillo, whose longest claws measure seven inches.

Ernie Bohner copes with a few armadillos at Persimmon Hill Farm in Stone County where he grows blackberries, blueberries and raspberries. Digging in mulch, the armadillos damage plant roots. "You fill it in, and they come and do it again, right in the same area," says Bohner, who has live-trapped and relocated several. Lacking appropriate bait, he wedges boards in a V shape at the trap's entrance and herds the animal in.

"They're a hoot to try to catch," he says good-naturedly. "For one thing, they're pretty darn fast. They jump across the ground instead of running. The thing that's hilarious is they'll forget they're being chased and they'll stop. You run up and try to capture them, and they'll remember again and run another 50 yards."

A struggling armadillo's claws can inflict damage, so a long-handled net is useful if capture is necessary. Cornered, the armadillo curls up in a semi protected ball. Due to its response to surprise, its most formidable (but accidental) predator is the automobile - jumping straight up is not an ideal strategy.

If your lawn hasn't been excavated, you might view armadillos with amusement and wonder. On a food plot at Drury-Mincy, an armadillo in the distance looks like an army helmet moseying along. Nose down and crowned with a crescent gleam of sunlight, it makes a constant whuff-whuff whuff sound as it sniffs and pokes into old diggings. When it digs, dirt flies out behind it, and its tail waves in a graceful curve.

In Missouri, armadillos are nocturnal in summer but shift their activity to daytime or evening in winter. I saw several on a sunny January afternoon when temperatures rose to the 50s.

Most were adults, but I also found two 5- to 6-pounders, possibly littermates. For a few minutes, they foraged together comically, two pink noses rummaging in the same hole. "When they're still young, they'll hang out together," says Kimberley Mackey, who studied the animals at Drury Mincy. "When they're older, they start going on their own."

The armadillo doesn't see well. Its hearing is better than its sight, but it often doesn't seem tuned in to humans approaching or talking. SMSU researchers think its sense of smell alerts it if the wind is right. Nevertheless, an armadillo may snuffle right to the feet of a human, realize something is odd, then simply change direction - or lope quickly away. Its leatherlike armor allows it to charge through brush and brambles without harm.

That armor is the intricately decorated skin of its head, back, sides and tail. Shoulder and haunch sections display a repeated small pattern, exquisitely detailed, and each band exhibits two rows of interlocking triangles. Younger adults are tan-gray with pink highlights; the oldest are gray.

There's more to admire than decoration, such as this amazing animal's two methods of crossing ponds and creeks. By swallowing air to inflate its stomach and intestines, it becomes buoyant and paddles on the surface. Or it sinks to the bottom and strolls across, postponing its next breath until it reaches the other side. Observers have reported underwater trips lasting six minutes.

And who wouldn't be impressed by the nine-banded's litters? The female releases only one ovum per year, but the embryo buds twice, producing genetically identical quadruplets, all males or all females, born with carapaces like soft pink leather.

Even more remarkable are the variable delays in pregnancies. After summer mating, implantation of the embryo in the uterine wall normally is delayed about 14 weeks. Gestation then takes four months, and pups are born in the spring. But implantation may be put off as long as 2 years, apparently when the female's environment isn't favorable for pups.

Though adults live one to a burrow (or sometimes in a hollow log), they may share space with other species. At SMSU's study site, infrared-activated cameras photographed rabbits, squirrels, opossums, wood rats and wood chucks entering and exiting armadillo burrows.

If you find armadillos so novel and appealing you're moved to adopt one, don't rush into it. They're not the best housemates. Glands near the tail emit a musky odor, and at night the little armored one will collide noisily with walls and attempt to dig through the floor. Better to let it snuffle around outdoors, digging and flinging those armadillo divots, doing what an armadillo does best.

EXPANDING ARMADILLOS

The nine-banded is still on the move. Theoretically, people on Cape Cod eventually could be in for a little armored surprise.

How far can armadillos go?

The limits probably will be determined by precipitation and winter weather, according to a paper in the Journal of Biogeography by James F. Taulman, Ph.D. graduate student at the University of Arkansas, Fayetteville, and Dr. Lynn W. Robbins, professor of biology, Southwest Missouri State University.

The armadillo's main food source, invertebrates, depends on moisture in the soil. The species' westward trek is expected to halt where precipitation drops below 38 cm (about 15 inches) per year, along the western borders of Kansas, Oklahoma and Texas.

Northward, precipitation is adequate, but winters are a problem. Armadillos don't hibernate and must eat, but ice and snow prevent digging. At Drury Mincy, after a week with snow on the ground, researchers found eight dead armadillos. Other armadillos, perhaps with more body fat, survived.

Taking into account winter temperatures and numbers of "freeze days," Taulman and Robbins predict armadillos could range into southern areas of Illinois, Indiana, Ohio, Pennsylvania, New York, Connecticut, Rhode Island and Massachusetts. The West Coast and several other western areas also are suitable for armadillos, should humans introduce the species there.

Although rivers define some present boundaries of the U.S. range, they aren't necessarily road blocks. Armadillos somehow crossed the Rio Grande and the Mississippi, and the SMSU survey revealed a few sightings on the north side of the Missouri.

Even so, the nine-banded's current range in Missouri is at its predicted northern limit, essentially the Missouri River. But Robbins cautions, "We're making an educated guess, and each time somebody has guessed, the armadillos kept moving north." The previous prediction set the limit in central Arkansas, "and they just plowed right on past that."

Robbins expects Missouri's armadillo population to increase and "fill in the gaps" in its range except for the bootheel, because of lack of burrow sites above the water table.

He thinks they won't do as well in broad expanses of farmland as they will where woods are available. Armadillos like the softer earth of fields and lawns, but when that open ground freezes, they head for the woods and feed under the leaf litter, where soil doesn't freeze as readily.


 

 

LEPROSY AND ARMADILLOS

The nine-banded armadillo is the key to a worldwide effort to eliminate Hansen's disease (leprosy), the ancient malady of the tropics and subtropics that affects cooler areas of the human body.

The leprosy bacillus was discovered in 1872, but scientists couldn't grow it in the laboratory. Research in treatment and prevention didn't take off until 100 years later, when scientists found an ideal host with a relatively cool body temperature - the nine-banded. Organisms grown in laboratory armadillos were distributed to research facilities, and the animal itself became a model in development of new drugs. As research continues, three medications are being tested in humans in clinical trials sponsored by the World Health Organization.

During this period of progress, two disconcerting mysteries arose in Texas and Louisiana. First, in the 1970s, leprosy was found in 15 to 20 percent of wild armadillos in those states, with the origin of their infection unknown.

Bob Howard, a spokesman for the National Center for Infectious Diseases, says the center has no information showing leprosy in armadillos in other states. "The armadillo is one of those animals that is studied pretty extensively," he explained, "so if there were indications it was occurring elsewhere, it would be picked up and studied." Florida Institute of Technology researchers found no leprosy among 3,000 armadillos, according to Dr. Arvind Dhople, research professor.

Then, in the mid-1980s, medical journals began to report diagnosis of leprosy in a few people in Texas and Louisiana who had no contact with leprosy patients but handled armadillos. Dhople estimates the number of diagnosed cases at five to ten per year. Contact included racing the armadillos, extracting meat and making souvenirs from the shells. The exact mode of transmission of leprosy, even from human to human, has not been clearly established, but Howard says, "We believe those particular behaviors would put one at risk."

As far as scientists know, both problems - leprosy in armadillos and in people who have handled them - are restricted to Texas and Louisiana.

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