Part II: Species Accounts248
Descriptive Notes
Body measurements: Shoulder height: 52–69 cm. Head and body
length: 96–117 cm. Body mass: 29.5–40 kg. The dental formula
for the Chacoan peccary is: I 2/3, C 1/1, P 3/3, M 3/3 (×2) = 38
(Sowls 1997).
The Chacoan peccary is larger and heavier than the other two
species. It also differs by its longer dorsal pelage, and a longer,
more concave rostrum, proportionally larger head and longer
ears, tail, and legs (Figure 23.2). The skull differs from the other
species of peccaries in having extreme development of the ros-
trum, nasal chambers and sinuses (Figure 23.3; Wetzel 1977b,
1981; Mayer & Wetzel 1986). It has a mixed coloration of various
shades of grey–brown, black, and white. Its fur is bristly, with a
dark mid-dorsal line running down the back and a light- coloured
band across the shoulders, similar to the collared peccary. The
juvenile’s pelage is a lighter colour, with a black back stripe, tan
shoulder collar, and white underside. The Chacoan peccary
does not have vestigial hind dew claws as the other two species
of peccaries do. The Chacoan peccary is the most morphologi-
cally specialized of the peccaries. The legs are relatively long and
adapted for running (Figure 23.4). The teeth are high-crowned,
suggesting that the species is a browser. The orbits are set well
back and its nasal chambers and sinuses are enlarged, possibly
as an adaptation to dry, dusty conditions (Mayer & Wetzel 1986).
Vision is poor, whereas olfaction and hearing are well developed
(Sowls 1984).
Like the other two species of peccaries, it has a large scent
gland on the rear of the back, about 15 cm above the base of the
tail. This gland is formed by a group of subcutaneous glands with
tubular glands around them. It appears as a raised area of skin,
approximately 5 × 7 cm along the dorsal mid line (Sowls 1997).
The gland produces a milky white substance used in marking
scent on objects and other peccaries. Females have four pairs ofmammae, one pair pectoral, two pairs abdominal, and one pair
inguinal (Sowls 1997).
Similar to the other two species, the Chacoan peccary does
not have a marked sexual dimorphism. Males have been found
to be slightly heavier than females except when they are preg-
nant (Handen 1994). The longevity of the species in the wild is
unknown. Sowls (1984), based on tooth cementum layers, esti-
mated the age of some individuals to be at least nine years. Some
individuals in captivity have reached 18 years (Proyecto Taguá,
Fortín Toledo, Paraguay).Habitat
The Chacoan peccary lives in a narrower variety of climates
than the other two species (Sowls 1997). Its primary habitat is
the drier part of the Gran Chaco ecoregion (Sowls 1984, 1997).
This is a markedly seasonal region, characterized by low rainfall
and high temperature. Temperatures rise from south to north
and rainfall from west to east. The main rainfall, as a result of
isolated storms, is from October to March; the driest months
are July and August. Annual rainfall ranges between 450 and
800 mm. Average annual temperature is 21.9°C with minima
below zero and maxima around 50°C. Average maximum is
near 27°C, and the absolute maximum may reach 47°C. The
average minimum is about 14°C, although freezing winter tem-
peratures can occur throughout the region. In addition to the
predominantly flat topography, the scarcity of rain results in
an arid zone that experiences frequent dust storms (Morello &
Adamoli 1968; Bucher 1983).
The dominant vegetative type of the species habitat is
xerophytic deciduous forests with multiple layers including a
canopy, subcanopy, shrub and herbaceous layer (Bucher 1983).
Schinopsis sp. and Aspidosperma quebracho-blanco are the
emergent trees, and Ruprechtia triflora, Capparis spp. and AcaciaFigure 23.2 Adult Chacoan peccary
in captivity at Proyecto Tagua,
Paraguay (photo by Juan M. Campos
Krauer). (A black and white version of
this figure will appear in some formats.
For the colour version, please refer to the
plate section.).02512:46:08