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Cabassous Chacoensis - Chacoan Naked-tailed Armadillo

Physical Description:

Cabassous chacoensis is one of the smallest species of the Dasypodidae family.  It has very small eyes and it is distinguished by its ears, which are very small and funnel-shaped.  The ears are widely separated with a fleshy extension at the anterior margin (Redford and Eisenberg 1992).  The armadillo is equipped with five sharp claws on the forefeet, with the third being the longest (MacDonald 1984).  This sickle-shaped claw aids in feeding and digging (Redford and Eisenberg 1992).  The head of Cabassous chacoensis is short and broad (Nowak 1999).  Wetzel (1980) recorded the ranges of 4 body measurements: total length, 300-306 mm; tail length, 90-96 mm; hind foot length, 61 mm; and ear length, 14-15 mm.  The weight is unspecified (Nixon 1995).  The tail of the armadillo is slender and shorter than the body.  Few armored plates are present on the tail; those that are present are small, thin, and widely separated (Redford and Eisenberg 1989).  This lack of complete armor makes Cabassous chacoensis a unique species.  The dorsal plates are arranged in traverse rows the entire length of the body (Redford and Eisenberg 1989).  The carapace of the armadillo is dark brown to black with yellowish edges.  The under parts are yellow-gray (Nixon 1995).  There are 10-13 moveable bands across the back (Nowak 1999).  Cabassous chacoensis has no teeth on the premaxilla bone.  The actual number of teeth varies from 7/8 to 10/9 on the upper and lower jaw respectively (Redford and Eisenberg 1989).  Cabassous chacoensis walks on the claws on its forefeet and the soles of its hind feet (Nixon 1995).  They do not usually move swiftly, but can run quickly for short distances if pursued (Nixon 1995, MacDonald 1984).  To escape predators or potential danger the armadillos usually burrow or go to water (Nixon 1995).


Cabassous chacoensis is confined to the xeric Chaco of Argentina and Paraguay as well as the gran Chaco of northwest Argentina, western Paraguay, southeast Bolivia and the adjacent part of Brazil (Redford and Eisenberg 1989).

Ontogeny and Reproduction:

Young are born singly.  The adults are considered solitary (Redford and Eisenberg 1992).

Ecology and Behavior:

Cabassous chacoensis lives in a variety of habitat including grasslands, semi-arid and moist lowlands, and uplands.  It prefers moist habitats with well-drained soil (Wetzel 1980).  They are a fossorial species, digging burrows in open ground and on river embankments (Nixon 1995).  Cabassous chacoensis generally feeds on ants and termites, which they locate by the smell of leaf litter and soil.  The long middle claw on the forefoot is used to cut small roots and to dig for food in rotting or dead roots.  The long tongue is used to extract insects from their tunnels (Nixon 1995).  Cabassous chacoensis is nocturnal. 


Cabassous chacoensis can be mistaken for Cabassous unicinctus (Wetzel 1982).  When handled, the males make a loud grunt while the females remain silent (Wetzel 1982).  Little is known of the armadillo and its natural history.  Only four individuals have been found and documented worldwide (Redford and Eisenberg 1989).  The Museum of Natural History in Paraguay has only one individual in its collection (Martinez 1996).

Literature Cited:

Macdonald, D. 1984.  Encyclopedia of Mammals.  Andromedia Oxford University.  Pp. 781-783.

Martinez, O. R.  1996.  Colecciones de Flora y Fauna del Mureo Nacional de Historia Natural del Paraguay.  San Lorezo, Paraguay.  Pg 481.

Nixon, J.  1995.  Minnesota State University website.  Accessed 13 November, 2004.

Nowak, R. M.  1999.  Walker’s Mammals of the World, 6th Edition, Volume 2. John   Hopkins University Press, Baltimore. Pp. 162-163.

Redford, K. H. and J. F. Eisenberg.  1989.  Mammals of the Neotropics, Volume 1.University of Chicago Press, Chicago.  Pg 99.

____________________________.  1992.  Mammals of the Neotropics, Volume 2.  University of Chicago Press, Chicago.  Pp. 52-54.

Wetzel, R. M.  1980.  Revision of the naked-tailed armadillos, genus Cabassous.  Ann Carnegie Museum 49:678-84.

___________.  1982a.  Systematics, distribution, ecology, and conservation of South American edentates.  In Mammalian Biology in South America, (eds) M. Mares and H. Genoways.  Pittsburgh, University of Pittsburgh, Special Publication             Series Pymatuning Laboratory of Ecology.  Pp 345-375.

___________.  1982b.  Mammals of Chaco of Paraguay.  Nat. Geog. Sos. Res. Repts. 14: 679-84.


Reference written by Shannon Murray, Biol 378 (Mammalogy), University of WisconsinStevens Point:  Edited by Chris Yahnke. Page last updated July 25, 2005.

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