Big Hairy Armadillo
Encyclopedia
Chaetophractus villosus, commonly called the Big Hairy Armadillo (of the family Dasypodidae) is one of the largest and most numerous armadillos in South America
. It lives from sea level to altitudes of up to 1,300 meters across the southern portion of South America and can be found in grasslands, forests, savannahs, and has even started claiming agricultural areas as its home. It is an accomplished digger and spends most of its time below ground. They make both temporary and long term burrows
depending on their food source. The armadillo can use specially evolved membranes in its nose in order to obtain oxygen from the surrounding soil particles without inhaling any of the soil itself. Armadillos are protected from predators by a series of thin bony plates along the head and back. They reach sexual maturity at around nine months and have been known to live over thirty years in captivity. Though this animal is routinely harvested for its meat and its shell, or simply killed for pestering farmers, it has shown amazing resiliency and populations seem to be handling this exploitation well. Because of this there are currently no protective practices in place for this armadillo but it does live in many protected areas. This species of armadillo is a preferred research animal due to its adaptability to the lab setting, and relative hardiness in situations of stress.
. The armadillo’s head and body are covered by protective bony plates, with its head plate being the most prominent. Along its back, flexible bands that encircle the torso allow flexibility in this otherwise stiff armor. The underside of this armadillo is densely covered in hair and this trait is how it got its common name. Long course hairs also project from the bony plates making this armadillo much hairier than its cousins. The average individual grows anywhere from 260 mm to 340 mm in body length by the time it reaches maturity. Powerful front claws are used for both foraging
and avoiding predators.
The genus Chaetophractus consists of two species, Chaetophractus vellerosus (Lesser Hairy Armadillo) and Chaetophractus villosus. These species are recognized by the large amount of hair that extends all over their body, but especially on their underside. The skulls follow the same patterns as other dasypodids however females exhibit longer bones in the rostrocaudal plane which is one of the key variables that shows the sexual dimorphism
of these species. Not much is known about the cranial morphology of these species especially bone by bone descriptions. More research is being done in order to better describe these species and the skeletal differences between them. For the time being, body size, habitat, and behaviors, are the best way to discern the differences.
a few noticeable traits stand out. The first difference is the size of these species, Chaetophractus villosus being the biggest, which can grow to a length of 340 cm. Chaetophractus vellerosus is much smaller, being able to fit in the palm of your hand when full grown, usually weighing only a kilogram. Both species are covered with much more hair than any other armadillos, mostly sprouting from its underside or between the bony plates along its back. When Chaetophractus villosus is sexually aroused with an erect penis it is easy to determine its species. Its penis can be as long as 35 cm long and usually remains completely withdrawn inside a skin receptacle. The Lesser Hairy Armadillo can usually be found in higher altitudes because its smaller size and slower metabolic rate helps it survive in an area that has less food.
containing osteoderms is one of the very distinctive features of armadillos and is true for fossil taxa as well. These elements are evident frequently in the paleontological record due to their resilience. Three distinct areas are recognized in these hardened plates. The outer and inner parts are made of thin compact bone, while the middle zone is thicker and contains tissues for hair follicles and sweat glands. The presence of red bone marrow is rare in members of Chaetophractus and yet widespread in Dasypus novemcinctus osteoderms. These findings propose an early split of both subfamilies and maintain the hypothesis that the Euphractinae
are more derived than the Dasypodinae.
Chaetophractus villosus earliest known fossils were found in the Pampean region which suggests that it is where the species originated. Fossil records then indicate the migration into Patagonia as the main dispersal route, which most likely occurred after the Pleistocenic glaciations. Using molecular dating scientists estimate that the first armadillos popped up aroud the Cretaceous/Tertiary boundary. This was followed by the divergence of anteaters and sloths in the Early Eocene era.
and Magallanes
, Chile
. It is found in the Grand Chaco of Bolivia, Paraguay, and Argentina and is starting to migrate south into the Tierra del Fuego
province of Argentina as well. It can be found in the Bio-Bio
province and south to Aisen province both in eastern Chile. Climate change and the opportunistic tendencies of this armadillo are allowing them to live in more and more areas. Unlike some of its cousins the Big Hairy Armadillo has not had as drastic of a change in its territory. This does not mean that this armadillo isn’t as affected by climatic change it just hasn’t migrated as far north as some other species.
, or subterranean
, lifestyle. Even with the added challenge of burrowing this armadillo maintains similar body mass ratios with non fossorial species and suggests that it has adapted to a burrowing lifestyle as a way to avoid extreme temperatures and predators, rather than any help it could receive from foraging.
Little is known about the haemostasis of this species. Platelet
counts are similar between sexes and they seem to remain similar even when in captivity. They are comparable to most other mammals and react in the same manner to proven agonists. More studies in this area could reveal biomedical advances but at the moment little is known.
Scientists conducted studies on the Chaetophractus villosus penis muscles revealed that this species very long penis exhibits variability. During its waking hours it remains hidden beneath a skin receptacle, until it becomes erect and it projects outside in a rostral
direction. During its slow wave sleep phase penile protrusion makes some very complex movements. The penis during this phase is non-erect but remains outside of its receptacle. During paradoxical sleep, no erections occur, and the penile muscles share the characteristics of the rest of the body.
there is a large species diversity among the fauna
. This is due to the diverse habitats on both the Chile and Argentinean sides of the Andes Mountains and the species that have evolved for each environment. Of these the rodents represent fifty percent of the mammalian population and carnivores another twenty-three percent. This armadillo has even been able to do quite well in captivity and become tame relatively quickly.
Chaetophractus villosus spends most of its time burrowing in the ground and looking for insects or worms as its main foraging method. Its powerful front claws and snout allow it to rout through the sediment with relative ease. When the armadillo detects a predator it will run to the nearest burrow and wedge itself in using its legs. In this way predators are left with nothing but the bony plates exposed. When it cannot get to one of its burrows it will lay down flat on the ground in order to better protect its softer underside.
Most of this armadillo’s activity occurs starting at dusk and continues on into the night. They can be seen active in the day, however, when enough food cannot be found during the night. It uses its sense of smell to find prey and shovels soil away in order to reach it. Most individuals breed in the late winter or spring but in captivity have been known to conceive year round. After a gestation period of 60 to 75 days the female will usually give birth to a litter of one to two young which are suckled for another 50 to 80 days.
Chaetophractus villosus seems to be able to burrow through most sediment
but tends to shy away from rockier terrains. It would also appear that they tend to burrow into the side of a hill rather than on flat ground. These armadillos make temporary burrows in search of food or safety that are usually shallow and less complex. Their home burrows are usually much deeper and can be quite complex, with many escape tunnels and dens. The orientation of their burrows depends largely on the wind orientation. This allows them to be well adapted to arid desert terrain.
at the moment. In fact on the endangered species scale this armadillo rates as a LC or least concern species. This is due to its large population and widespread habitat range. It also has a remarkable ability to adapt to many changing environments. It is considered a least concern species because it is not predicted to decrease into any of the threatened categories any time soon. In fact the Big Hairy Armadillo populations seem to be growing.
Because of the large amount of biodiversity
in these regions many temperate ecoregions are now under protection. By not only protecting individual species but also the habitat that they live in, many species can benefit from these protected areas. This ensures that the species that live in them can maintain a diverse ecosystem and gives them a sanctuary limiting the influence of man. Without this protecting individual species would be a challenge due to loss of habitat or other influential variables.
South America
South America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...
. It lives from sea level to altitudes of up to 1,300 meters across the southern portion of South America and can be found in grasslands, forests, savannahs, and has even started claiming agricultural areas as its home. It is an accomplished digger and spends most of its time below ground. They make both temporary and long term burrows
Burrows
Burrows is a provincial electoral division in the Canadian province of Manitoba. It was created by redistribution in 1957, and formally came into existence in the provincial election of 1958. The riding is located in the northern part of Winnipeg....
depending on their food source. The armadillo can use specially evolved membranes in its nose in order to obtain oxygen from the surrounding soil particles without inhaling any of the soil itself. Armadillos are protected from predators by a series of thin bony plates along the head and back. They reach sexual maturity at around nine months and have been known to live over thirty years in captivity. Though this animal is routinely harvested for its meat and its shell, or simply killed for pestering farmers, it has shown amazing resiliency and populations seem to be handling this exploitation well. Because of this there are currently no protective practices in place for this armadillo but it does live in many protected areas. This species of armadillo is a preferred research animal due to its adaptability to the lab setting, and relative hardiness in situations of stress.
Species Description and Taxonomy
Chaetophractus villosus or Big Hairy Armadillo is the most abundant species of armadillo in ArgentinaArgentina
Argentina , officially the Argentine Republic , is the second largest country in South America by land area, after Brazil. It is constituted as a federation of 23 provinces and an autonomous city, Buenos Aires...
. The armadillo’s head and body are covered by protective bony plates, with its head plate being the most prominent. Along its back, flexible bands that encircle the torso allow flexibility in this otherwise stiff armor. The underside of this armadillo is densely covered in hair and this trait is how it got its common name. Long course hairs also project from the bony plates making this armadillo much hairier than its cousins. The average individual grows anywhere from 260 mm to 340 mm in body length by the time it reaches maturity. Powerful front claws are used for both foraging
Foraging
- Definitions and significance of foraging behavior :Foraging is the act of searching for and exploiting food resources. It affects an animal's fitness because it plays an important role in an animal's ability to survive and reproduce...
and avoiding predators.
The genus Chaetophractus consists of two species, Chaetophractus vellerosus (Lesser Hairy Armadillo) and Chaetophractus villosus. These species are recognized by the large amount of hair that extends all over their body, but especially on their underside. The skulls follow the same patterns as other dasypodids however females exhibit longer bones in the rostrocaudal plane which is one of the key variables that shows the sexual dimorphism
Sexual dimorphism
Sexual dimorphism is a phenotypic difference between males and females of the same species. Examples of such differences include differences in morphology, ornamentation, and behavior.-Examples:-Ornamentation / coloration:...
of these species. Not much is known about the cranial morphology of these species especially bone by bone descriptions. More research is being done in order to better describe these species and the skeletal differences between them. For the time being, body size, habitat, and behaviors, are the best way to discern the differences.
Diagnosis
When trying to determine the differences between these species of ChaetophractusChaetophractus
Chaetophractus is a small genus of armadillos in the Dasypodidae family. It contains the following three species:*Screaming Hairy Armadillo, Chaetophractus vellerosus*Big Hairy Armadillo, Chaetophractus villosus...
a few noticeable traits stand out. The first difference is the size of these species, Chaetophractus villosus being the biggest, which can grow to a length of 340 cm. Chaetophractus vellerosus is much smaller, being able to fit in the palm of your hand when full grown, usually weighing only a kilogram. Both species are covered with much more hair than any other armadillos, mostly sprouting from its underside or between the bony plates along its back. When Chaetophractus villosus is sexually aroused with an erect penis it is easy to determine its species. Its penis can be as long as 35 cm long and usually remains completely withdrawn inside a skin receptacle. The Lesser Hairy Armadillo can usually be found in higher altitudes because its smaller size and slower metabolic rate helps it survive in an area that has less food.
Fossil Record
The presence of a carapaceCarapace
A carapace is a dorsal section of the exoskeleton or shell in a number of animal groups, including arthropods such as crustaceans and arachnids, as well as vertebrates such as turtles and tortoises. In turtles and tortoises, the underside is called the plastron.-Crustaceans:In crustaceans, the...
containing osteoderms is one of the very distinctive features of armadillos and is true for fossil taxa as well. These elements are evident frequently in the paleontological record due to their resilience. Three distinct areas are recognized in these hardened plates. The outer and inner parts are made of thin compact bone, while the middle zone is thicker and contains tissues for hair follicles and sweat glands. The presence of red bone marrow is rare in members of Chaetophractus and yet widespread in Dasypus novemcinctus osteoderms. These findings propose an early split of both subfamilies and maintain the hypothesis that the Euphractinae
Euphractinae
Euphractinae is a subfamily of armadillo in the Dasypodidae family. It contains the following genera:*Calyptophractus*Chaetophractus Hairy Armadillos*Chlamyphorus*Euphractus six-banded armadillos*Zaedyus pichis...
are more derived than the Dasypodinae.
Chaetophractus villosus earliest known fossils were found in the Pampean region which suggests that it is where the species originated. Fossil records then indicate the migration into Patagonia as the main dispersal route, which most likely occurred after the Pleistocenic glaciations. Using molecular dating scientists estimate that the first armadillos popped up aroud the Cretaceous/Tertiary boundary. This was followed by the divergence of anteaters and sloths in the Early Eocene era.
Geographic Distribution
Chaetophractus villosus home range encompasses the Pampas and Patagonioa as far south as Santa Cruz, ArgentinaArgentina
Argentina , officially the Argentine Republic , is the second largest country in South America by land area, after Brazil. It is constituted as a federation of 23 provinces and an autonomous city, Buenos Aires...
and Magallanes
Magallanes Province
Magallanes Province is one of four provinces in the southern Chilean region of Magallanes and Antártica Chilena . The provincial capital is the city of Punta Arenas.-Geography and demography:...
, Chile
Chile
Chile ,officially the Republic of Chile , is a country in South America occupying a long, narrow coastal strip between the Andes mountains to the east and the Pacific Ocean to the west. It borders Peru to the north, Bolivia to the northeast, Argentina to the east, and the Drake Passage in the far...
. It is found in the Grand Chaco of Bolivia, Paraguay, and Argentina and is starting to migrate south into the Tierra del Fuego
Tierra del Fuego
Tierra del Fuego is an archipelago off the southernmost tip of the South American mainland, across the Strait of Magellan. The archipelago consists of a main island Isla Grande de Tierra del Fuego divided between Chile and Argentina with an area of , and a group of smaller islands including Cape...
province of Argentina as well. It can be found in the Bio-Bio
Bío-Bío
Biobío or Bío-Bío may refer to several places in Chile:* Biobío River, the second longest river in Chile and the southern frontier of the Kingdom of ChileAdministrative divisions:* Biobío Region, eighth region of Chile...
province and south to Aisen province both in eastern Chile. Climate change and the opportunistic tendencies of this armadillo are allowing them to live in more and more areas. Unlike some of its cousins the Big Hairy Armadillo has not had as drastic of a change in its territory. This does not mean that this armadillo isn’t as affected by climatic change it just hasn’t migrated as far north as some other species.
Ecology
Members of Dasyposidae including Chaetophractus villosus have evolved very interesting and specific traits in order to help it survive. The most recognizable of these are the bony plates that cover the armadillos head and back. These protective plates allow the individual a fair measure of protection against its natural predators. This armadillos also has a remarkable respiratory adaptation when the nostrils are completely covered in soil. It is able to maintain sufficient respiratory movements due to a mechanism that allows it to use air that fills the space between soil particles, without inhaling the particles themselves. This along with its powerful digging claws and low body mass ratio contribute to this fossorialFossorial
A fossorial organism is one that is adapted to digging and life underground such as the badger, the naked mole rat, and the mole salamanders Ambystomatidae...
, or subterranean
Subterranean
Subterranean or The Subterranean may refer to:* Subterranea , underground structures, both natural and man-madeIn literature:* The Subterraneans, a novella by Jack Kerouac...
, lifestyle. Even with the added challenge of burrowing this armadillo maintains similar body mass ratios with non fossorial species and suggests that it has adapted to a burrowing lifestyle as a way to avoid extreme temperatures and predators, rather than any help it could receive from foraging.
Little is known about the haemostasis of this species. Platelet
Platelet
Platelets, or thrombocytes , are small,irregularly shaped clear cell fragments , 2–3 µm in diameter, which are derived from fragmentation of precursor megakaryocytes. The average lifespan of a platelet is normally just 5 to 9 days...
counts are similar between sexes and they seem to remain similar even when in captivity. They are comparable to most other mammals and react in the same manner to proven agonists. More studies in this area could reveal biomedical advances but at the moment little is known.
Scientists conducted studies on the Chaetophractus villosus penis muscles revealed that this species very long penis exhibits variability. During its waking hours it remains hidden beneath a skin receptacle, until it becomes erect and it projects outside in a rostral
Rostral
Rostral can refer to:* Anatomical location or direction, towards the rostrum .* Rostral bone, in ceratopsian dinosaurs* Rostral column, a monumental scaled column, frequently decorated with ship bows* Rostral scale, in scaled reptiles...
direction. During its slow wave sleep phase penile protrusion makes some very complex movements. The penis during this phase is non-erect but remains outside of its receptacle. During paradoxical sleep, no erections occur, and the penile muscles share the characteristics of the rest of the body.
Life History and Behavior
In PatagoniaPatagonia
Patagonia is a region located in Argentina and Chile, integrating the southernmost section of the Andes mountains to the southwest towards the Pacific ocean and from the east of the cordillera to the valleys it follows south through Colorado River towards Carmen de Patagones in the Atlantic Ocean...
there is a large species diversity among the fauna
Fauna
Fauna or faunæ is all of the animal life of any particular region or time. The corresponding term for plants is flora.Zoologists and paleontologists use fauna to refer to a typical collection of animals found in a specific time or place, e.g. the "Sonoran Desert fauna" or the "Burgess shale fauna"...
. This is due to the diverse habitats on both the Chile and Argentinean sides of the Andes Mountains and the species that have evolved for each environment. Of these the rodents represent fifty percent of the mammalian population and carnivores another twenty-three percent. This armadillo has even been able to do quite well in captivity and become tame relatively quickly.
Chaetophractus villosus spends most of its time burrowing in the ground and looking for insects or worms as its main foraging method. Its powerful front claws and snout allow it to rout through the sediment with relative ease. When the armadillo detects a predator it will run to the nearest burrow and wedge itself in using its legs. In this way predators are left with nothing but the bony plates exposed. When it cannot get to one of its burrows it will lay down flat on the ground in order to better protect its softer underside.
Most of this armadillo’s activity occurs starting at dusk and continues on into the night. They can be seen active in the day, however, when enough food cannot be found during the night. It uses its sense of smell to find prey and shovels soil away in order to reach it. Most individuals breed in the late winter or spring but in captivity have been known to conceive year round. After a gestation period of 60 to 75 days the female will usually give birth to a litter of one to two young which are suckled for another 50 to 80 days.
Chaetophractus villosus seems to be able to burrow through most sediment
Sediment
Sediment is naturally occurring material that is broken down by processes of weathering and erosion, and is subsequently transported by the action of fluids such as wind, water, or ice, and/or by the force of gravity acting on the particle itself....
but tends to shy away from rockier terrains. It would also appear that they tend to burrow into the side of a hill rather than on flat ground. These armadillos make temporary burrows in search of food or safety that are usually shallow and less complex. Their home burrows are usually much deeper and can be quite complex, with many escape tunnels and dens. The orientation of their burrows depends largely on the wind orientation. This allows them to be well adapted to arid desert terrain.
Conservation
Chaetophractus villosus is one of the armadillo species that is not in danger of extinctionExtinction
In biology and ecology, extinction is the end of an organism or of a group of organisms , normally a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and recover may have been lost before this point...
at the moment. In fact on the endangered species scale this armadillo rates as a LC or least concern species. This is due to its large population and widespread habitat range. It also has a remarkable ability to adapt to many changing environments. It is considered a least concern species because it is not predicted to decrease into any of the threatened categories any time soon. In fact the Big Hairy Armadillo populations seem to be growing.
Because of the large amount of biodiversity
Biodiversity
Biodiversity is the degree of variation of life forms within a given ecosystem, biome, or an entire planet. Biodiversity is a measure of the health of ecosystems. Biodiversity is in part a function of climate. In terrestrial habitats, tropical regions are typically rich whereas polar regions...
in these regions many temperate ecoregions are now under protection. By not only protecting individual species but also the habitat that they live in, many species can benefit from these protected areas. This ensures that the species that live in them can maintain a diverse ecosystem and gives them a sanctuary limiting the influence of man. Without this protecting individual species would be a challenge due to loss of habitat or other influential variables.