Hmmm – it seems that most of my posts open this way. I hope you all don’t mind that I use my research efforts as fodder for this blog. Anyway, to continue, I wanted to insert an ‘armadillo incident’ in my current work in progress, which is set in northeast Texas in 1894. Today armadillos can be found throughout much of the state (the exception being the Trans-Pecos region). But what kind of range did they have in 1894?. So I started digging around for information, and along the way I discovered some interesting facts about the strange looking critters and their migration into the US.
First off, I assume most of you know what an armadillo looks like (see the pictures included here if you don’t) but for those of you who have never actually encountered a real life armadillo face-to-face, here are some statistics: The common name for the armadillo found in the United States is the Nine-banded Armadillo. The adult animal is about the size of a terrier, its upper body is encased in a bony carapace with large shields on its shoulders and rump, with nine bands in between (thus the name). Average size is 2.5 feet in length and about 13.5 lbs in weight. They have 30-32 peg-like teeth and strong claws that aid in their burrowing.
What my research uncovered was that the armadillo didn’t make an appearance in the US until after 1850. After that date, however, the armadillo incursion took place with amazing rapidity. In fact, the magnitude of their annual range expansion is almost ten times faster than the average rate expected for mammals.
Learning this tidbit, I immediately began to wonder what changed at about the 1850 mark. Digging deeper I discovered that there were three major roadblocks that initially held the armadillos back.
The first of these was the Rio Grande River. Even though armadillos are good swimmers, the Rio Grande is a formidable waterway and very few armadillos would attempt such a crossing, and few of those who did survived the conditions on the other side. Which leads to the second factor, which was
Predators. Not only would the wolves and panthers of Northern Mexico and South Texas have kept the population at bay, but man hunted them as well since armadillos were highly prized for their meat. (Still are – hubby informs me that he has eaten armadillo and found it quite tasty).
And lastly there was the matter of habitat. While armadillos can and do survive in a number of different settings and environments, their dwelling of preference is brushy or forested terrain. Prior to 1850, south Texas experienced annual fires (both natural and man made) that left the area covered in large part by prairie grass.
All of these factors changed when American settlers began colonizing Texas in the later half of the nineteenth century. Armadillos were able to take advantage of the increase in human traffic across the Rio Grande, to find opportunities for safer travel themselves. In fact, it’s likely that many were deliberately brought across as a potential food source. And the presence of humans also served to decrease the population of the natural predators such as the above mentioned wolves and panthers. And the halting of the yearly burn-offs allowed mesquite brush to gain a foothold in the open grasslands, providing a more armadillo-friendly habitat. The subsequent development of this territory for pasture and crop use gave the armadillo population an additional leg up as it made the land an even more suitable environment for their habitation.
So that explains how they came to immigrate to this country. But what factors played into their rapid expansion once they made it to the US? By nature, armadillos normally don’t stray far from the area of their birth – unless the population is high. It seems armadillos have a high reproductive rate, with females regularly producing their young in sets of identical quadruplets. As favorable conditions allowed their numbers to increase, they began to range farther from home. And with life spans up to twenty years, it only took a small number of the animals to establish stable populations in new territories.
Of course, man helped speed things up along the way. Armadillos managed to stow away on railcars that were used to transport of cattle from Texas to other states. They were also carried to other locations as curiosities and then later escaped or were released in the wild. For example, the Florida population had its genesis in 1924 when armadillos were set loose from a small zoo during a storm, and their foothold was further strengthened when several more escaped from a traveling circus in 1936.
Another interesting fact I learned about armadillos is how they cross a body of water . Not surprisingly, because of their heavy shell, they tend to sink. When crossing a very narrow body of water, like a ditch or small stream, the armadillo will simply walk across the bottom underwater – in fact it can hold its breath for up to six minutes. When faced with a wider body of water, however, the armadillo has the ability to ingest air, enough, in fact, to inflate its stomach and intestines to twice their normal size. This increases the animal’s buoyancy, allowing it to swim across. Once it reaches land again, it will usually take several hours for the animal to release all of this extra air from its body. The mechanism armadillos employ to accomplish this is still something of a mystery to scientists, but it appears to be a voluntary rather than autonomic response.
Oh, and as for my story, I did discover that armadillos became common in east Texas at around the 1900 mark. Which means, it is probably safe to assume that a few of them had reached that area by 1894. Or at least that’s my story and I’m sticking to it…