Chapter 23: Chacoan peccary Catagonus wagneri (Rusconi, 1930)251
peccaries probably obtain sufficient water from the cactus they
consume. The Chacoan peccary can live in drier areas than the
collared peccary, probably because its kidneys are more effi-
cient at concentrating urine and thus conserve additional water
(Zervanos 1985).
Reproduction and Growth
Mayer and Brandt (1982) and Sowls (1984) found a slightly
biased sex ratio in favour of males from observation of animals
in the wild, specimens collected and examination of fetuses.
However, Yahnke et al. (1997) reported that the sex ratio of new-
borns in captivity did not differ from 1:1. The species apparently
reproduce once per year in the Paraguayan and the Bolivian
Chaco and the farrowing season extends from September to
January (Taber et al. 1993; Noss 1999; Noss et al. 2003) with
peaks of births in September and October (Yahnke et al. 1997).
Litter sizes have been reported to range between one and four
with an average ranging between 2 and 2.4 in Paraguay (Mayer &
Brandt 1982; Brooks 1992; Yahnke et al. 1997). However, these
data come from small sample sizes or from captive animals,
making it problematic to infer to wild populations (Noss 1999).
Taber et al. (1993) estimated a litter size of 1.7 for a wild popula-
tion and suggested that the difference could be a result of low
reproductive rate or high neonate mortality. In the Argentine
Chaco, local hunters report that findings of three or four fetuses
are exceptional (Altrichter 2005). The litter size of pregnant
harvested females in Argentina ranged from one to three with a
mode of two (Altrichter 2005).
Captive females in Paraguay gave birth between 1.2 and 8.3
years of age and there were no differences in litter size among
age groups or among females, although it seems that younger
females may have smaller litters (Yahnke et al. 1997). Gestation
time in captivity is about 150 days (Benirschke & Heuschele
1993).
Behaviour
Social and Community Behaviour
Chacoan peccaries are social, living in smaller herds compared
to the other two peccary species. It has a similar spatial organiza-
tion to that of the collared peccary, which exhibits a stable group
structure and mutual avoidance between groups (Day 1985;
Taber et al. 1993). The herd sizes in the Paraguayan Chaco were
reported in the past to vary between 1 and 10 (Mayer & Brandt
1982; Sowls 1997), with an average of 3.8 (Mayer & Brandt 1982)
and 4.3 (Sowls 1984; Taber et al. 1994). However, group sizes
are smaller in hunted areas, ranging from one to four (Mayer &
Brandt 1982; Taber et al. 1993; Altrichter & Boaglio 2004).
Herds observed in the Bolivian Paraguay ranged between 1 and
7 individuals with an average of 2.6 (Maffei et al. 2008). Herds
are composed of both sexes and probably composed of family
groups (Sowls 1997). However, it is common to observe solitary
Chacoan peccaries (Mayer & Brandt 1982); in fact, locally in
Bolivia it is often called ‘solitario’.
Like the other species of peccaries, they communicate by
various sounds, ranging from grunts to chatters of the teeth.
Tooth-chattering, however, is less common among Chacoan
peccaries than in the other species (Handen & Benirschke
1991). They also display physical interactions among members
of the herd, rubbing against each other. Some aggressive behav-
iour, such as charging and biting, has been observed among
individuals. The social structure of herds is unknown, although
it has been proposed that there is not a dominance hierarchy in
the herds (Mayer & Brandt 1982; Handen & Benirschke 1991).
However, Brooks (1996) proposed that there is a subtle hierar-
chical structure. He observed one animal leading the herd from
one area to another on several occasions. He also recorded a
female being dominant over others, and having prefered access
to food. Benirschke and Heuschele (1993) reported that a matri-
arch appeared to be dominant in three captive herds. Brooks
(1996) believes that social order between genders is complex
and remains largely unknown. This non-hierarchial nature
between genders is probably explained by the polygynandrous
mating strategy (Brooks 1992). Brooks (1996) concluded that
social contact is a major factor influencing group bonding.
Additionally, low guttural grunts and olfactory cues aid in
bonding.
The Chacoan peccary is territorial and marks territory with
the odorous substance secreted from glands on their backs
by rubbing against objects like trees, shrubs, logs, rocks, etc.
Taber et al. (1994) reported that the Chacoan peccary defends
territory based upon little overlap between neighbouring
ranges and the use of marking stations. Individuals in the
wild have been observed bathing in dust and mud. In search
of dust, they often use dirt roads. They use scat stations peri-
odically over months or years (Taber et al. 1993). When fright-
ened, Chacoan peccaries raise the long hairs on their back and
spray secretions from their dorsal gland, presumably to keep
the group together in the dense brush by odour (Taber 1993;
Brooks 1996).Parasites and Diseases
Internal parasites have been found only rarely in Chacoan
peccaries. Ticks and fleas are also not very prevalent, at least
in captivity (Benirschke & Heuschele 1993). Taber (1991)
reported that individuals and groups of Chacoan peccaries
were found dead or dying from disease in the northern and
western Paraguayan Chaco between 1979 and 1981. Although
the nature of the disease was unknown, both foot-and-mouth
disease and bovine rabies were common in the region in the late
1970s. During that decade, large numbers of cattle were brought
into this area. Taber suggested that the Chacoan peccary in
north-western Paraguay had previously had little exposure and,
hence, little immunity to livestock diseases (Taber 1989, 1991).
A study on susceptibility to selected diseases found that pecca-
ries have medium susceptibility to rinderpest and low suscepti-
bility to foot-and-mouth disease, vesicular stomatitis, vesicular
exanthema, rabies, and classical swine fever. New World pec-
caries are not susceptible to African swine fever (Fowler 1996).
Coccidioidomycosis has been reported in peccaries, but sus-
ceptibility is low. Cryptococcosis has also been reported in
peccaries in a zoo. Peccaries are not an important source of
zoonotic diseases (Fowler 1996)..02512:46:08