Cabassous chacoensis
Chacoan Naked-tailed Armadillo
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 funnelshaped. 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
(McCarthy 1982) (not in lit cited). 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 underparts 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 hindfeet (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).
Distribution:
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).
Ontology 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.
Remarks:
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.
http://www.msu.edu/~nixonjos/armadillo/cabassous.html 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.
Written by Shannon Murray, Bio 378