By Elizabeth Gonsiorowski
Geographic Range
Calyptophractus retusus (greater fairy armadillos) is native to South America. These armadillos inhabit the Gran Chaco region of western and central Boliva, northern Argentina and Paraguay. (Grzimek, 1998)
Biogeographic Regions:
neotropical 
(native ).
Habitat
Calyptophractus retusus inhabits the dry grasslands of Argentina, Paraguay and Bolivia. They lives in underground burrows in warm and dry soils. They often burrow near anthills.
These animals are found in the following types of habitat:
temperate ; terrestrial .
Terrestrial Biomes:
savanna or grassland .
Physical Description
(2.2 lbs)
The distinguishing characteristic of Calyptophractus retusus (along with a similar species, Chlamyphorus truncatus) is its pelvic armor, which is firmly attached to the spine and pelvic bones, unlike other members of the family Dasypodidae. The soft dorsal armor is entirely fused to the skin, and there are 24 dorsal bands that are mobile due to the soft tissue between them. The white hair is sparse on the dorsal surface, but dense and woolly on the underbelly. There are curved claws on the hands and powerful, sharp claws designed for burrowing on the feet. The soft armor appears to be cut off at the end, making it appear truncated. The head shield is less well-defined than is that of Chlamyphorus truncatus, and it lacks a posterior row of large scutes. Total body length ranges from 140 to 175 mm and tail length is about 35 mm. The teeth are small and peg-like. (Grzimek, 1998)
Some key physical features:
endothermic ; heterothermic ; bilateral symmetry .
Sexual dimorphism: sexes alike.
Reproduction
The reproductive behavior of Calyptophractus retusus has not been studied in great detail because this species is extremely rare and has never bred in captivity. After mating occurs, the fertilized egg remains in the female's uterus for up to several months. The exact gestation period is unknown, but it can be inferred that it is similar to the average armadillo gestation period (120 days). Calyptophractus retusus gives birth to several offspring at a time; the usual litter size is four. Amazingly, these offspring are the result of a single egg. In other words, this particular species gives birth to quadruplets on a regular basis!
When its young are born, their armor is soft, and it takes several weeks for it to harden. However, young greater fairy armadillos are able to walk within hours of birth. For most armadillos, weaning takes place within several weeks of birth. The specific length of time for the greater fairy armadillo is unknown. The average sexual maturity is six to twelve months. (Brown, 1997)
Key reproductive features:
iteroparous ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; viviparous .
Lifespan/Longevity
Average life span is twelve to fifteen years.
Behavior
Calyptophractus retusus lives in underground burrows and does not usually venture above ground. They are rare and nocturnal, and scientists have not had the opportunity to study the behavior of these animals in great detail. They are excellent burrowers and can escape into soil rapidly. Once they have formed a burrow they may use their truncated rear plate to effectively block the burrow entrance. C. retusus has been observed making crying sounds, similar to those made by human infants. (Nowak and Paradiso, 1983)
Food Habits
The eating habits of Calyptophractus retusus are similar to those of other armadillos. They eat insects, insect larvae, worms, snails, roots, and small seeds, although an individual held in captivity was able to live off of boiled rice and grapefruit. (Grzimek, 1998)
Primary Diet:
omnivore .
Animal Foods:
eggs; insects; terrestrial non-insect arthropods; mollusks; terrestrial worms.
Plant Foods:
roots and tubers; seeds, grains, and nuts; fruit.
Economic Importance for Humans: Negative
South American armadillos have been known to host the parasitic insects that carry Chagas' disease, but there have not been any documented cases of Calyptophractus retusus hosting the disease. (Storer et al., 1972)
Economic Importance for Humans: Positive
Because some armadillo species are known to suffer from leprosy, they have been used in research efforts to find new treatments for this disease. Armadillos may help to control insect pests. (Brown, 1997)
Ways that people benefit from these animals:
research and education; controls pest population.
Conservation Status
IUCN Red List: [link]:
Near Threatened.
US Federal List: [link]:
No special status.
CITES: [link]:
No special status.
Specific threats to Calyptophractus retusus are poorly known, but these animals are rare and endangered. Their natural habitat is shrinking at a steady pace as a result of conversion to agriculture, and there is little protected land in the areas where they live. For example, 2.88% of land in Paraguay is dedicated to the preservation of wildlife. Domestic dogs and over-collecting also pose a threat to greater fairy armadillos. (Grzimek, 1998)
Other Comments
Calyptophractus retusus was discovered in 1859 by Hermann Burmeister in Bolivia. A native person showed him the mummified remains of an animal that he was unfamilar with, and it was brought to various institutions for further study. Greater fairy armadillos were previously known as Chlamyphorus retusus.
For More Information
Find Calyptophractus retusus information at
Contributors
Elizabeth Gonsiorowski (author), West Windsor Plainsboro High School.
Joan Rasmussen (editor), West Windsor-Plainsboro High School.
