Biology Reference
In-Depth Information
ing. Worms, insects, grubs, and other small invertebrates make up a large part of the armadillo's diet.
It also has a long, sticky tongue, somewhat like an anteater's, which is handy for dredging up ants and
termites. Soft fruits, berries, birds' eggs, and carrion also find their way down the armadillo's rather
unfussy gullet.
Because so much of the armadillo's food comes from grubs, worms, ants, and other subterranean in-
vertebrates, the right kind of soil is a critical factor in armadillo habitat. Soft soil will support a denser
population of armadillos than harder soil, and if the soil in an area is excessively hard, armadillos won't
live there.
In some areas of the United States and Mexico, armadillos are regarded as a serious threat to the
nests of quail, turkeys, and chickens. This appears to be a bum rap that isn't supported by the evidence.
One study, for example, found the remains of eggs in only five of 281 armadillo stomachs. It appears
likely that armadillos are simply being blamed for the depredations of other creatures.
As already noted, the armadillo is a master digger. If the ground is reasonably soft, it can dig its way
out of sight in a just a minute or so. This remarkable aptitude for speedy excavation is due to the arma-
dillo's feet, which are admirably equipped for the task. The middle toes—two of the four on the front
feet and three of the five on the rear feet—are the longest and are tipped with formidable claws.
Because armadillos have only a few vestigial hairs on their bodies, they are not well insulated against
either heat or cold. When the weather is hot, armadillos are mostly active from evening until dawn; in
cold weather, they're mainly active during the warmest part of the afternoon, and they can't survive in
areas subject to prolonged spells of subfreezing weather.
When the weather is either too cold or too hot, armadillos spend much of their time in dens. These
are mostly burrows in the ground as much as fifteen feet long, although they also use dens in the rocks.
Great diggers that they are, armadillos usually have numerous burrows. In hot, dry country, they often
congregate around streams and water holes, where they take cooling mud baths.
A suit of armor is by no means the armadillo's only unusual feature. This oddity among mammals is
full of surprises, and its reproductive style is every bit as bizarre as its outward appearance. For openers,
armadillo copulation itself is decidedly different from that of most mammals. Although the creature's
nine middle plates give it a good deal of flexibility, it isn't sufficient for the standard “mount from the
rear” approach. As an added complication, its genitals are located underneath. Undaunted, armadillos
surmount this obstacle with ease by having the female turn on her back during mating.
The armadillo's aberrant traits continue after breeding. Mating mostly occurs in July, but the fertil-
ized egg from a July mating doesn't attach to the uterus until November. This phenomenon, known as
delayed implantation, also occurs in members of the weasel family and among bears (for a detailed de-
scription of its advantages, see chapter 14), but it's far from the mammalian norm.
But wait—the reproductive ways of the armadillo become even more bizarre! The single fertilized
egg divides into four embryos; after implantation, these share the same placenta and grow into identical
quadruplets of the same sex. Thus an armadillo always bears either four male or four female young.
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