Cerdocyon thous
Crab-eating fox
Description:
The coat of the Crab-eating fox varies across its body. The back and sides are
mixed with brown and gray which gives a yellowish tint (Nowak 1999). The underside
of its coat is brownish white (Nowak 1999). The face, ears, and fronts of the legs are
orange to brown or light brown in color, while the tips of the ears and backs of the legs
are black (Berta 1982). The ears are short and the tail is long and bushy and is dark
pigmented or just the tip is black (Nowak 1999). Adults weigh from six to seven
kilograms, and they can range from 900 to 1000 mm in length from the head to the tip of
the tail (Nowak 1999).
Figure 1: Crab-eating fox
Distribution:
The Crab-eating fox ranges from northern South America in Colombia and
Venezuela, along the eastern part of the continent, and south into Paraguay, Brazil,
Uruguay, and Northern Argentina (Berta 1982). They inhabit regions of savannah and
woodland areas (Berta 1982). Specific to Paraguay, the subspecies Cerdocyon thous
entrerianus is the only Crab-eating fox found in Paraguay of the 5 subspecies of Crabeating foxes (Berta 1982).
Figure 2: Distribution of Crab-eating fox
Ontogeny and Reproduction:
All information found on the reproduction of the Crab-eating fox has been done in
captivity (Berta 1982). Gestation in the Crab-eating fox ranges from 52 to 59 days (Berta
1982). They have two litters a year at about 8 month intervals, and their litter size varies
from 3 to 6 pups (Nowak 1999). At birth the eyes and ears are closed and they have no
teeth (Berta 1982). Their eyes open about 14 days after birth (Nowak 1999). Their
weight ranges from 120 to 160 grams (Berta 1982). Their coat color begins as charcoal
gray then by day 20 after birth it begins to change until they achieve their adult coat at
about day 35 (Berta 1982).
After the young are born, they enter three stages of development: early nesting
stage, mixed nutritional dependency stage, and post weaning dependency stage (Berta
1982). The early nesting stage begins on day one of birth and lasts until day 30, and it is
where the young depend on the mother’s milk for nutrition (Berta 1982). The mixed
nutritional dependency stage lasts from days 30 to 90, and in this time the young become
completely weaned (Berta 1982). The final stage, post weaning dependency stage, lasts
from 90 days to 5 months, and this is where the young’s nutrition comes mostly from
solid food (Berta 1982). The young become sexually mature within their first year of life
at about 9 months (Nowak 1999).
Ecology and Behavior:
Even though the fur of the Crab-eating fox is not valuable, the fox is hunted
constantly (Berta 1982). The Crab-eating fox is nocturnal and hunts alone but may travel
in pairs (Berta 1982). Changes in their hunting area are related to the distribution and
availability of prey in the wet and dry seasons which cause a shift in their diet as the
seasons pass (Berta 1982). The Crab-eating fox is omnivorous and helps control
populations of small mammals, insects, and crabs by incorporating them into its diet
(Nowak 1999). Along with small mammals, insects, and crabs, the Crab-eating fox has
been found to eat fish and birds according to an analysis of their scats (Farrell, Roman, &
Sunquist 2000).
Literature Cited:
Berta, A. 1982. Cerdocyon thous. Mammalian Species, No: 186: 1-4.
Farrell, Laura E., Joseph Roman, Melvin E. Sunquist. 2000. Dietary separation of
sympatric carnivores identified by molecular analysis of scats. Molecular
Ecology 9(10): 1583.
Nowak, R. 1999. Walker’s Mammals of the World, Sixth Edition. Baltimore and
London: John Hopkins University Press.
Reference by Katherine Olejnichak, Biol 378: Edited by Kim Moore. Page last updated 12-14-04.