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Calyptophractus retususgreater fairy armadillo(Also: Chacoan fairy armadillo)

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)

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.

Physical Description

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)

  • Sexual Dimorphism
  • sexes alike
  • Average mass
    1 kg
    2.20 lb

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)

  • Average number of offspring
    4
  • Range age at sexual or reproductive maturity (male)
    6 to 12 months

Lifespan/Longevity

Average life span is twelve to fifteen years.

  • Typical lifespan
    Status: wild
    12 to 15 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)

Communication and Perception

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)

  • 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: 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)

  • Positive Impacts
  • research and education
  • controls pest population

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)

Conservation 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.

Contributors

Elizabeth Gonsiorowski (author), West Windsor-Plainsboro High School, Joan Rasmussen (editor), West Windsor-Plainsboro High School.

Glossary

Neotropical

living in the southern part of the New World. In other words, Central and South America.

World Map

acoustic

uses sound to communicate

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

chemical

uses smells or other chemicals to communicate

endothermic

animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.

fossorial

Referring to a burrowing life-style or behavior, specialized for digging or burrowing.

heterothermic

having a body temperature that fluctuates with that of the immediate environment; having no mechanism or a poorly developed mechanism for regulating internal body temperature.

iteroparous

offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).

motile

having the capacity to move from one place to another.

native range

the area in which the animal is naturally found, the region in which it is endemic.

nocturnal

active during the night

omnivore

an animal that mainly eats all kinds of things, including plants and animals

sedentary

remains in the same area

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

solitary

lives alone

tactile

uses touch to communicate

temperate

that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).

terrestrial

Living on the ground.

tropical savanna and grassland

A terrestrial biome. Savannas are grasslands with scattered individual trees that do not form a closed canopy. Extensive savannas are found in parts of subtropical and tropical Africa and South America, and in Australia.

savanna

A grassland with scattered trees or scattered clumps of trees, a type of community intermediate between grassland and forest. See also Tropical savanna and grassland biome.

temperate grassland

A terrestrial biome found in temperate latitudes (>23.5° N or S latitude). Vegetation is made up mostly of grasses, the height and species diversity of which depend largely on the amount of moisture available. Fire and grazing are important in the long-term maintenance of grasslands.

visual

uses sight to communicate

viviparous

reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.

References

Accessed Aug. 19, 2000 at http://www.surdelsur.com/flora/biogeogr/glosario/zoo.htm.

Brown, A. 1997. Pp. 80-105 in Encyclopedia of Mammals, vol.1. New York: Mc Graw Hill.

Grzimek, D. 1998. Pp. 622-625 in Grzimek's Encyclopedia: Mammals. New York: Mc Graw Hill.

Nowak, R., J. Paradiso. 1983. Pp. 460-468 in Walker's Mammals of the World, 4th ed. vol.1. Baltimore: John's Hopkins University Press.

Storer, , Usinger, Stebbins, Nybakker. 1972. Pp. 803 in General Zoology. New York: Mc Graw Hill.

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