Katherine Olejnichak
Species Account
12/03/04
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 head the tip of tail (Nowak 1999).
Distribution
The Crab-eating fox ranges from north 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 sub
species Cerdocyon thous entrerianus is the only Crab-eating
fox found in Paraguay of the 5 subspecies of Crab-eating fox (Berta 1982).
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, about 8 month intervals, and their litter size varies
from 3 to 6 pups (Nowak 1999). At birth the young’s eyes and ears and closed and the
have no teeth (Berta 1982). The young’s 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).
As the days pass 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 days one of birth and lasts until
days 30, and is where the young depend on the mother’s milk for nutrition (Berta). The
mixed nutritional dependency stage lasts from days 30 to 90, and in this time the young
become completely weaned (Berta). 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).
References
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.