Nine-Banded Armadillo (Dasypus novemcinctus)

The claws on the front feet of this critter leave little doubt it is 

well adapted for digging.

Nine-banded Armadillos live in my world -- or do I live in their world?  Neither of us is native to the Ozarks, though armadillos have inhabited the Earth much longer than humans.

The Nine-banded Armadillo's ancestors lived quite comfortably in South America until around three million years ago when the formation of the Isthmus of Panama allowed them to start moving north.  They've been heading north ever since.  Armadillos were first recorded in south Texas in the early nineteenth century.  Many researchers thought the dillers' northward migration would be severely limited by cold weather.  Armadillos have a slow metobolic rate, little fat and lack the ability to regulate their body temperatures as well as most mammals.  However, Nine-banded Armadillos proved to be much more adaptable than early researchers thought.  By 1995 the species had become well-established in Texas, Oklahoma, Louisiana, Arkansas, Mississippi, Alabama, and Florida, and had been sighted as far afield as Kansas, Missouri, Tennessee, Georgia and South Carolina. A decade later, the armadillo had become established in all of those areas and continued its migration, being sighted as far north as southern Nebraska, southern Illinois, and southern Indiana.  (There is also ample evidence humans introduced armadillos into several southern states where they thrived.) (Source:  Wikipedia)

That I was able to take these photos during the middle of the afternoon, illustrates one of the  Nine-banded Armadillos' adaptations to colder temperatures.  They are normally nocturnal, but when the weather is cold, dillers remain in their underground burrows all night and come out to forage during the warmer parts of the day.

The bands on the Nine-banded Armadillo's carapace

are the basis for its common name, but it can actually have between

7 and 11 bands.  I only count eight bands on this individual.

Armadillos are primarily insectivores.  They dig up and eat a wide variety of bugs, larvae, grubs, etc.  However, stomach content analysis has show dillers will eat pretty much any small critter that doesn't get out of their way, including small reptiles, amphibians and birds.  Their digging behavior often makes armadillos unpopular among gardeners and those dedicated to having beautiful lawns.  I have no interest in maintaining a convention lawn, but do find it exasperating when a diller "tills" a well-mulched vegetable garden bed.

A previous post shows an armadillo litter out foraging.  (Armadillo litters are always identical quadruplets.)  Other sources of more information than you ever really wanted to know about these unique critters include Mammals of Texas, Biogeography of  the Nine-Banded Armadillo and Armadillo Fact File.

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Nine-Banded Armadillo (Dasypus novemcinctus)

Armadillo Herd

A litter of young armadillos foraging in our yard late Wednesday afternoon.

Armadillos have a unique reproductive scheme. Only one egg is fertilized. That egg divides and the resulting two eggs also divide once. Hence, a normal armadillo litter is always identical quadruplets.

Adult armadillos are solitary. After leaving their nest burrow, litter mates remain together for a relatively brief time before going their separate ways.

For more information on the Nine-banded Armadillo (Dasypus novemcinctus), please see:
The Mammals of Texas

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Armadillo Herd

Armadillo Redux

When the local armadillo population learned about my recent blog post featuring one of their dear, departed brethren, they dispatched a representative into the backyard during daylight. I understood that I was supposed to photograph an intact member of the species, so I did. You'd think that a professional model armadillo would have learned to stand still during a photo shoot, but this was not the case.

Armadillo Redux

Armadillo on the Half-Shell

Nine-Banded Armadillo (Dasypus novemcinctus)

Something enjoyed a good meal the other night. I cannot be certain of the predator, of course, but assumed it was a coyote that got lucky and managed to flip the diller over and administer a disabling bite to its unprotected underside. Predatory pressure on armadillos in the Ozarks is relatively light due to our lack of large predators – unless you consider cars and trucks predators. It's said that a large predator with strong jaws can crush the armadillos shell, but I don't think a coyote is large enough to do this. (A friend says that his Rottweiler can.)

Armadillos are mammals. Their closest living relatives are sloths and anteaters. There are twenty species of armadillos, but only the nine-banded is found in the United States. Many South American species are threatened due to habitat destruction. The nine-banded is doing just fine and rapidly expanding its range.

Expansion: There were few armadillos in the U. S. prior to the late 1800s. In 1995 dillers were firmly established in Texas, Oklahoma, Arkansas, Louisiana, Alabama, Mississippi and Florida. A decade later armadillos were also a common sight in Kansas, Missouri, Tennessee, Georgia and South Carolina, and had been seen as far north as southern Nebraska, southern Illinois and western Kentucky. Researchers estimate that the armadillo can establish populations as far north as Nebraska and New York.

Humans played a major role in the rate of armadillo territorial expansion. By and large, we have stopped eating them. We've eliminated most of the large predators that ate them. We altered habitat, resulting in more of the brushy areas they prefer. And, in numerous cases both intentional and accidental, humans introduced armadillos into new territory. Additionally, the armadillo reproduction success rate is high and they are fairly flexible when it comes to diet.

Food: Armadillos primarily eat insects, especially those buried in soil or rotting wood. The dillers root along in the soil making grunting noises like small pigs. Long and strong claws make armadillos extremely proficient at digging. Like anteaters, they slurp up the insects with their tongues which are coated with a sticky saliva. The will also eat amphibians, tiny mammal young, bird eggs and carrion. In areas where animal matter is in short supply, armadillos will switch to a more vegetarian diet.

Reproduction: Mating in North America usually takes place in July and August, but implantation of the zygote is delayed until November. In times of extreme stress, implantation can be delayed even longer. Females captured and held in isolation have given birth as much as two years after their capture date. Gestation is 120 days after implantation.

Before development begins, the fertilized egg divides. The resulting two cells also divide once. Therefore, a normal armadillo litter is four identical quadruplets.

Swimming: When faced with a body of water it wants to cross, an armadillo has two choices. If the body of water is small, the armadillo can simply hold it's breath (for up to six minutes) and walk underwater to the opposite side. The weight of its shell keeps the diller anchored to the bottom of the stream. Armadillos can also swim. They are able to gulp air into their stomachs and intestines to provide buoyancy.

Behavior (Primarily based upon personal observations.): Armadillos seem to be fairly oblivious creatures with only marginal fear of humans. I suppose this is because they have few natural predators. You cannot quite walk up to a diller and poke it with a stick, but almost. Sometimes when I've tried to approach a diller in the open, it has seen me coming and scampered off. Other times, I've been able to walk up within a few feet of a feeding diller. The armadillo has continued to feed for several minutes before “suddenly” noticing me and moving on.

When severely startled, an armadillo is said to be able to jump three or four feet straight up. This is a survival mechanism in the wild, but works to the diller's disadvantaged when being passed over by a vehicle on the highway. I have never seen an armadillo jump anything like that high. The usually just give a slight little jump before scamping away. Perhaps I'm just not as startling as an 18-wheeler.

Most gardeners consider armadillos pests. Dillers are primarily nocturnal. You can end the day with a nicely mulched and maintained raised bed out in the garden and wake up to a bed that looks as if it has been tilled and partially spread over the adjoining aisles. Any seedlings or recent transplants in the bed are history.

(A note on the bottom two photos: This litter showed up at the edge of our yard back in May, 2005. This is the one and only time I've ever seen a litter that was still together. Armadillos are solitary and usually go their separate ways as soon as they leave the nest. We had just gotten our current camera, our first digital. We'd never used it and weren't even sure how to turn it on. Jo decided that these armadillos were an event that could not be missed without at least trying to take photos. The camera was supposed to be able to point and shoot and she was determined to test that hypothesis. I'm glad she did. The photo of the single armadillo is cropped from the very first photo taken with the camera we are still using.)

Sources, additional information and/or photos:

Expansion
Habitat, ecology and biology
Swimming
Jumping

Armadillo on the Half-Shell

Electric Garden Fence

The electric fence surrounding our gardening just didn't seem to be working up to snuff the other day. There was abundant evidence that an armadillo had made several unauthorized tilling forays into the garden, and Jo said she'd watched a coon enter and leave the garden through the electric fence, barely giving a glance back over his shoulder upon exiting -- like maybe he'd felt a little tingle but certainly didn't get zapped. When I touched the little fence tester doodad to the wires, the light flashed as it should, but the pulse of light was weak.

I decided that the tall grass under the fence might be draining off too much of the juice. Even though our grass is growing slowly these days, it had still gotten tall enough to reach the bottom fence wire, especially on the west end of the garden. So...... I dragged out my trusty Weedeater and trimmed the grass under the fence all the way around. While trimming on the back side of the garden, I also discovered that a metal pepper cage had rolled up against the electric fence.

When I finished trimming, I again tested the fence. This time I was getting a bright flash of light and even an audible click whenever the fence cycled on. That ought to be enough juice to zap any raccoon. I'm not really certain what effect the electric fence will have on an armadillo unless he touches his nose to the wire. Trimming the grass may have helped, but I suspect that removing the wire cage accounted for the majority of the improvement.

Electric Garden Fence