Chaco crimson-nosed rats are native to the Neotropical region and can be found in the province of Misiones in northeastern Argentina and in southeastern Paraguay. (D'Elia and Pardinas, 2008)
- Terrestrial Biomes
- savanna or grassland
- Range elevation
- 300 (high) m
- 984.25 (high) ft
- Average elevation
- 125 m
- 410.10 ft
Chaco crimson-nosed rats are members of the subfamily Sigmodontinae, which have a dental formula of 1/1, 0/0, 0/0, 3/3, for a total of 16 teeth. This species has short ears, a short tail, and enlarged claws. Like other members of Bibimys, can has a crimson nose. Lateral pelage of the torso tends to have a buffy appearance and is dark along the dorsal surface of the body. Ventral pelage is whitish and slight buffy in appearance. On average, chaco crimson-nosed rats weigh 28.6 g and have a total body length of 162.9 mm. Tail length ranges from 35 mm to 81 mm, with an average of 66.14 mm. Hind foot length (including the claw) averages 21.9 mm and ranges from 20 to 25 mm. Ear length averages 16.3 mm and ranges from 16 mm to 18 mm. The number of roots of the third molar can be used to distinguish Chaco crimson-nosed rats from other members of the genus Bibimys. Chaco crimson-nosed rats have 3 roots, while most other members of Bibimys have only 2. (D'Elia, et al., 2008; Eisenberg and Redford, 1999)
- Range mass
- 19.2 to 40.5 g
- 0.68 to 1.43 oz
- Average mass
- 28.6 g
- 1.01 oz
- Range length
- 132 to 185 mm
- 5.20 to 7.28 in
- Average length
- 162.9 mm
- 6.41 in
Currently, there is no information available on the mating system of.
Little information is available on the reproductive behavior of Akodon, close relatives to Bibimys, typically have breeding seasons extending from August to May but may vary according to climate and resource availability. Litters consist of 3 to 4 young and there are usually 2 litters per year. In one species of Akodon, Akodon azarae, implantation may be delayed and gestation last 22.7 days on average. (Nowak, 1999). Members of the genus
- Key Reproductive Features
- gonochoric/gonochoristic/dioecious (sexes separate)
- Parental Investment
The chaco crimson-nosed rat's lifespan has not been documented.
The general behavior of this species has not been thoroughly studied. However, it is known that Akodon can be diurnal, nocturnal, crepuscular, or active at any time. Members of the closely related genus Akodon typically dig small burrows that end in globular nests. (Eisenberg and Redford, 1999; Nowak, 1999)is fossorial. Members of the related genus
Communication and Perception
Communication in sigmodontine rodents perceive their environment using vision, hearing, touch, smell, and taste. Sigmodontines primarily use auditory or chemical cues for communication with conspecifics. (Nowak, 1999)is not well understood. Other
- Communication Channels
There is insufficient information on the feeding habits of Akodon cursor and Akodon boliviensis, close relatives of , show that typical Akodon diet consists of plant material, seeds, and insects. The stomach contents of A. azarae is 25% plant matter and 75% invertebrates. (Eisenberg and Redford, 1999; Nowak, 1999). However, stomach content analysis of both
The only documented predator of this species is the white-tailed hawk (Buteo albicaudatus), however other raptors and carnivores likely prey on this species as well. The small size of and its fossorial behavior help protect it from predators. Its brown pelage likely helps camouflage it from potential predators. (Eisenberg and Redford, 1999)
- Anti-predator Adaptations
- Known Predators
- White-Tailed Hawk (Buteo albicaudatus)
- Ecosystem Impact
- soil aeration
- sucking lice, Hoplopleura aitkeni
Economic Importance for Humans: Positive
There is no information on the potential positive effects ofon humans.
Economic Importance for Humans: Negative
There is no information on the potential negative impacts ofon humans.
Although (D'Elia and Pardinas, 2008)lives in a confined region of Argentina and Paraguay, this species is listed as "least concern" by the IUCN Red List of Threatened Species and is not protected under the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES).
The genus Bibimys is very diverse and poorly understood. Trapping members of this genus is difficult and for that reason, many specimens are very old and badly preserved. Currently, there are only three species of Bibimys, however, the validity of the three species, , Bibimys labiosus, and Bibimys torresi, has not been researched extensively. (Pardinas, et al., 2005)
Jonathan Haun (author), University of Michigan-Ann Arbor, Phil Myers (editor), University of Michigan-Ann Arbor, John Berini (editor), Animal Diversity Web Staff.
living in the southern part of the New World. In other words, Central and South America.
uses sound to communicate
young are born in a relatively underdeveloped state; they are unable to feed or care for themselves or locomote independently for a period of time after birth/hatching. In birds, naked and helpless after hatching.
- 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.
uses smells or other chemicals to communicate
having markings, coloration, shapes, or other features that cause an animal to be camouflaged in its natural environment; being difficult to see or otherwise detect.
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.
Referring to a burrowing life-style or behavior, specialized for digging or burrowing.
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).
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.
chemicals released into air or water that are detected by and responded to by other animals of the same species
- scent marks
communicates by producing scents from special gland(s) and placing them on a surface whether others can smell or taste them
reproduction that includes combining the genetic contribution of two individuals, a male and a female
- soil aeration
digs and breaks up soil so air and water can get in
uses touch to communicate
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).
Living on the ground.
the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.
- 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.
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.
uses sight to communicate
reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.
D'Elia, G., I. Mora, P. Myers, R. Owen. 2008. New and Noteworthy Records of Rodentia (Erethizontidae, Sciuridae, and Cricetidae) from Paraguay. Zootaxa, 1784: 39-57.
D'Elia, G., U. Pardinas. 2008. "IUCN Red List of Threatened Species" (On-line). Accessed March 16, 2011 at http://www.iucnredlist.org/apps/redlist/details/2801/0.
Eisenberg, J., K. Redford. 1999. Mammals of the Neotropics: The Central Neotropics. The University of Chicago, Illinois: The University of Chicago Press.
Granzinolli, M., J. Motta-Junior. 2006. Small Mammal Selection by the White-Tailed Hawk in Southeastern Brazil. The Wilson Journal of Ornithology, 118: 91-98. Accessed April 07, 2011 at http://www.faunaparaguay.com/Granzinolliwilson118.pdf.
Nowak, R. 1999. Walker's Mammals of the World, vol. II. Baltimore and London: The Johns Hopkins University Press. Accessed April 18, 2011 at http://books.google.com/books?id=7W-DGRILSBoC&pg=PR2&dq=walker's+mammals+of+the+world+volume+2&hl=en&ei=4q-sTbvkBIHLgQecy8XzBQ&sa=X&oi=book_result&ct=result&resnum=1&ved=0CCwQ6AEwAA#v=onepage&q&f=false.
Pardinas, U., G. D'Elia, P. Myers. 2005. "An Introduction to the Genus Bibimys (Rodentia: Sigmodontidae): Phylogenetic Position and Alpha Taxonomy" (On-line). Accessed March 16, 2011 at http://evolucion.fcien.edu.uy/guillermo/bibimys.pdf.
Pardinas, U., P. Teta. 2007. Mammalia, Didelphimorphia, Didelphidae, Chacodelphys formosa (Shamel, 1930): Range extension. Check List, 4: 333-335. Accessed March 16, 2011 at http://www.checklist.org.br/getpdf?NGD034-07.
Webb, K., M. Miller, G. Martin. 2010. "Gran Chaco" (On-line). Britannica Online Encyclopedia. Accessed April 06, 2011 at http://www.britannica.com/EBchecked/topic/240998/Gran-Chaco.