ArticlePDF Available

A review of wild boar Sus scrofa diet and factors affecting food selection in native and introduced ranges

Authors:
  • National Scientific and Technical Research Council - Patagonia Norte

Abstract and Figures

The wild boar Sus scrofa is an omnivore with one of the largest geographical ranges of all species. However, no synthesis exists on its diet, feeding behaviour and factors affecting food selection in its native and introduced ranges.A literature review and a test of effect size revealed significant differences in wild boar diet composition in native and introduced ranges. Wild boar diet is dominated by plant material (∼90%) in both ranges, but animal matter and fungi are consumed in greater proportions in the introduced range than in the native range. Food items frequently include agricultural crops (especially in the native range) and endangered animal species (especially in the introduced range). Energy requirements, food availability, and seasonal and geographical variations are major factors influencing food selection by wild boar. These factors may also interact with human activities (e.g. agricultural crops, supplementary feeding) to influence diet composition further.Dietary studies should be more rigorous and consistent across ranges to allow better comparisons. A detailed study of diet in combination with seasonal patterns of habitat use could provide key information such as target species and susceptible habitats on which management efforts should focus.
Content may be subject to copyright.
REVIEW
A review of wild boar Sus scrofa diet and factors affecting
food selection in native and introduced ranges
Sebastián A. BALLARI* Departamento de Diversidad Biológica y Ecología, Universidad Nacional de
Córdoba-CONICET, Avenida Vélez Sársfield 299, 3er. Piso, Córdoba 5000, Argentina.
E-mail: sebastianballari@gmail.com
M. Noelia BARRIOS-GARCÍA‡ Department of Ecology and Evolutionary Biology, University of
Tennessee, 569 Dabney Hall, Knoxville Tennessee 37996, USA. E-mail: mbarrios@utk.edu
Keywords
feral pig, foraging, predation, rooting,
scavenging
*Correspondence author.
‡Present address: Department of Zoology,
University of British Columbia #4200–6270
University Boulevard, Vancouver, BC V6T1Z4,
Canada.
Submitted: 6 February 2013
Returned for revision: 25 April 2013
Revision accepted: 2 August 2013
Editor: KH
doi:10.1111/mam.12015
ABSTRACT
1. The wild boar Sus scrofa is an omnivore with one of the largest geographical
ranges of all species. However, no synthesis exists on its diet, feeding behaviour
and factors affecting food selection in its native and introduced ranges.
2. A literature review and a test of effect size revealed significant differences in
wild boar diet composition in native and introduced ranges. Wild boar diet is
dominated by plant material (90%) in both ranges, but animal matter and fungi
are consumed in greater proportions in the introduced range than in the native
range. Food items frequently include agricultural crops (especially in the native
range) and endangered animal species (especially in the introduced range). Energy
requirements, food availability, and seasonal and geographical variations are
major factors influencing food selection by wild boar. These factors may also
interact with human activities (e.g. agricultural crops, supplementary feeding) to
influence diet composition further.
3. Dietary studies should be more rigorous and consistent across ranges to allow
better comparisons. A detailed study of diet in combination with seasonal patterns
of habitat use could provide key information such as target species and susceptible
habitats on which management efforts should focus.
INTRODUCTION
Wild boars Sus scrofa have highly plastic diets, and their
ability to adapt to diverse foods has allowed them to estab-
lish populations in almost every location where they have
been introduced (Genov 1981a, Rosell et al. 2001, Baubet
et al. 2004, Irizar et al. 2004). Wild boars are opportunistic
omnivores feeding on all types of organic matter and some-
times on inorganic materials like stones, mud and plastic
(Schley & Roper 2003, Massei & Genov 2004, Herrero et al.
2005, Hafeez et al. 2011). The diet of the wild boar has been
well studied in some parts of its native range (Genov 1981a,
Asahi 1995, Fournier-Chambrillon et al. 1995, Sáenz de
Buruaga 1995, Baubet et al. 2004, Herrero et al. 2004, 2005,
2006, Irizar et al. 2004, Cellina 2008) and its introduced
range (Challies 1975, Rudge 1976, Everitt & Alaniz 1980,
Wood & Roark 1980, Howe et al. 1981, Baber & Coblentz
1987, Thomson & Challies 1988,Chimer a et al. 1995, Taylor &
Hellgren 1997, Adkins & Harveson 2006, Desbiez 2007,
Skewes et al. 2007, Cuevas et al. 2010, Cuevas et al. 2013), but
there are no syntheses or comparisons between native and
introduced ranges in terms of diet composition and feeding
behaviour.
Depending on the habitat type, wild boars may carry out
different trophic functions, acting as crop pests, frugivores,
predators, destroyers of seed banks and plant dispersers
(Genov 1981b, Geisser & Reyer 2004, Bueno et al. 2011,
O’Connor & Kelly 2012). These functions are carried
out through four main feeding behaviours: browsing
and grazing (grasses, herbs, stems, leaves), foraging on the
ground (fruits, fungi, animal matter), rooting (rhizomes,
roots, invertebrates), and predation (vertebrates; Thomson &
Challies 1988, Baubet et al. 2004, Wilcox & Van Vuren 2009,
Bueno et al. 2011). Overall, wild boars seem to show
bs_bs_banner
Mammal Review ISSN 0305-1838
1Mammal Review (2013) © 2013 The Mammal Society and John Wiley & Sons Ltd
no particular foraging preference except for plant matter
over animal matter (Schley & Roper 2003, Massei & Genov
2004, Herrero et al. 2005, Adkins & Harveson 2006, Keuling
2007, Wilcox & Van Vuren 2009). However, some authors
emphasize their preference for a few items: stenophagy
(Herrero et al. 2006). For example, Herrero et al. (2005)
found that wild boars feed on a few abundant preferred items
that are highly digestible and nutritious, such as acorns from
the downy oak Quercus humilis.
Studies of the diet composition are important to determine
target species, food categories (plant vs. animal matter) and
seasonal variation, which may allow prediction of when and
why certain plant or animal communities might be impacted
(Wood & Roark 1980). Determining diet composition can aid
in understanding how wild boars use different ecosystems and
consequently in identifying their role in the food web (Baubet
et al. 2004). The aim of this study is to compare the diet and
feeding patterns of wild boars in their native and introduced
ranges, with special emphasis on introduced ranges, because
these environments are not adapted to support the species
(Barrios-Garcia & Ballari 2012, Spatz & Mueller-Dombois
1972, Nogueira-Filho et al. 2009). By means of a literature
review, we also assess how variation in food availability,
habitat use and behavioural patterns is reflected in the diet.
Understanding feeding habits in combination with seasonal
patterns of space and habitat use may inform management
plans.
METHODS
We conducted a literature search for articles using the key-
words ‘diet’, ‘feed*’, ‘wild boar’ and ‘Sus scrofa’ in the search
engine ISI Web of Knowledge and also checked the refer-
ences cited in all papers we found. We set the search for
studies between 1970 and 2013 and included studies refer-
ring to wild boar, feral pigs and hybrids.
The literature search yielded 145 studies, of which 78 were
relevant to wild boar diet (Appendix S1). Thirty-nine studies
were conducted in the native range and 39 in the introduced
range. The majority of the studies were focused on descriptive
aspects of diet such as diet composition and feeding habits
(n=45, Fig. 1). Many studies were focused on impacts such as
predation, damage to plant species, habitat degradation and
crop damage (n=31), or on processes or patterns such as
rooting and seed dispersal (n=20). Only 12 studies were on
nutritional aspects of the diet, and six were on management
aspects.
To determine the relative contribution of food items in
the native and introduced ranges, we used the log-response
ratio. We extracted data from 36 studies in which the dietary
composition was listed in terms of frequency and percent-
age stomach volume of plant and animal matter as well as
fungi (Appendix S2). The response ratio was calculated as
ln(XN/XI), where XNis the mean of the response variable
in the native range, and XIis the mean of the response in
the introduced range of wild boar (Hedges et al. 1999,
Osenberg et al. 1999). A response ratio of 0 (or if the confi-
dence intervals overlaps 0) indicates that wild boar diet does
not differ between the ranges. A positive response ratio
indicates that the diet includes the item in a greater propor-
tion in the native range, whereas a negative response ratio
indicates a greater use of the food item in the introduced
range.
RESULTS AND DISCUSSION
Importance of plant matter
Wild boar diet in both native and introduced ranges con-
sists primarily of plant matter including bulbs, roots, aerial
parts, fruits and seeds (Briedermann 1976, Wood & Roark
1980, Genov 1981a, Baber & Coblentz 1987, Schley & Roper
2003, Baubet et al. 2004, Keuling 2007, Giménez-Anaya
et al. 2008). The response ratio indicates that the volume of
plant matter consumed is slightly greater in the native range
than in the introduced range (Fig. 2).
In the native range, the frequency and volume of
plant matter are very high, 99% and 93%, respectively
0
10
20
30
40
50
Descriptive Impacts Patterns and
processes
Nutrition al
or
physiological
Management
Number of studies
Introduced range Native range
Fig. 1. Main objectives of wild boar studies
used in this review (a single study could have
more than one objective).
A review of wild boar Sus scrofa diet S. A. Ballari and M. N. Barrios-García
2Mammal Review (2013) © 2013 The Mammal Society and John Wiley & Sons Ltd
(Appendix S2). Herrero et al. (2005) found that above-
ground parts of plants comprise up to 71% of the volume,
whereas below-ground parts comprise 24% of the volume.
Authors disagree about the importance of below-ground
plant parts. On the one hand, Eriksson and Petrov (1995) in
the Ukraine found that the diet contains little leaf material
and lots of roots (35%), whereas on the other hand, Genov
(1981a) and Irizar et al. (2004) argue that roots and bulbs
are of no importance as foods. The ratio of above-ground to
below-ground plant material in the diet is determined by
the season (see ‘Factors affecting food selection’ below).
Wild boars eat fruits and seeds (Durio et al. 1995,
Fournier-Chambrillon et al. 1995, Sáenz de Buruaga 1995,
Irizar et al. 2004, Herrero et al. 2005), which provide a great
source of energy during periods of food scarcity (Barrett
1978, Belden & Frankenberger 1990, Loggins et al.
2002). For example, in France, acorns of holly oak
Quercus ilex were found in 90% of sampled stomachs
(Fournier-Chambrillon et al. 1995).
Wild boars may act as seed dispersers (endozoochory and
epizoochory) or simply as seed predators (Campos & Ojeda
1997, Heinken & Raudnitschka 2002, Schmidt et al. 2004,
Sanguinetti & Kitzberger 2010, Dovrat et al. 2012). In the
native range, Herrero et al. (2006) found that wild boars
are not important seed dispersers because the seeds they
consume are too large to avoid damage during digestion.
Similarly, Dovrat et al. (2012) found that although wild
boars can disperse seeds (mostly introduced plants), few of
them survive, whereas Wiedemann et al. (2009) showed that
maize seeds found in wild boar faeces retain their germina-
tion capacity only in extremely rare cases. In contrast,
other authors show that seed dispersal by wild boars
is important for both native and introduced plants
(Heinken & Raudnitschka 2002, Schmidt et al. 2004, Matías
et al. 2010, O’Connor & Kelly 2012).
In the introduced range, plant matter occurs in 99% of
the samples, whereas the volume is slightly smaller than
in the native range (87%, Fig. 2, Appendix S2). Some
authors emphasize the importance of leaf intake. For
example, Chimera et al. (1995) in New Zealand found that
leaves of Anisotome antipoda were the largest single food
item, and in the Galapagos Islands (Ecuador), forbs
appeared to be highly preferred over grasses (Coblentz &
Baber 1987). Similarly, in Texas, USA, Everitt and Alaniz
(1980) found that forbs make up more of the diet (56%)
than any other classes of food items. Fruits are also impor-
tant in the introduced range; in Brazil, Desbiez (2007)
found that fruit fibres make up approximately 60% of wild
boar faecal samples. Fruits were also found to be important
food items in the USA (Wood & Roark 1980) and in New
Zealand (Thomson & Challies 1988). Roots comprise 17%
of volume, less than fruits, forbs and grasses (Wood &
Roark 1980, Thomson & Challies 1988).
The role of wild boars as seed predators or dispersers in
the introduced range is debated. In the Brazilian Pantanal,
Desbiez (2007) showed that the weight of crushed seeds
never exceeds the weight of intact seeds in the stomach,
indicating that wild boars effectively transport and disperse
native seeds. By contrast, Campos and Ojeda (1997) and
Sanguinetti and Kitzberger (2010) found that wild boars eat
and destroy seeds of the shrub Prosopis flexuosa and the tree
Araucaria araucana in Argentina.
Importance of animal matter
Typically, wild boars consume animal matter frequently but
at low total volume (Appendix S2, Howe et al. 1981, Hahn
& Eisfeld 1998, Irizar et al. 2004, Herrero et al. 2006, Skewes
et al. 2007, Giménez-Anaya et al. 2008). All authors high-
light the low proportion of animal matter, but some empha-
size its importance as an essential dietary component
(Fournier-Chambrillon et al. 1995, Sáenz de Buruaga 1995).
For example, Fournier-Chambrillon et al. (1995), Keuling
(2007), and Wilcox and Van Vuren (2009) argue that
though the proportion of animal food is low, the impor-
tance of this type of food should not be underestimated
given its high digestibility. In the USA, animal matter rarely
exceeds 2% of the diet but occurs in 94% of stomachs
(Howe et al. 1981), suggesting that animal matter is
required for the species. In their native range, Herrero et al.
(2006) in Spain found that wild boars feed on a variety of
terrestrial arthropods, which are energetically rewarding. In
contrast, Genov (1981b) indicated that in Poland, animal
Fig. 2. Response ratios of food items in the diets of wild boars in their
native and introduced ranges. A positive ratio indicates a greater use of
a food item in the native range; a negative ratio indicates a greater use
in the introduced range. Symbols represent means; bars show 95%
confidence intervals.
S. A. Ballari and M. N. Barrios-García A review of wild boar Sus scrofa diet
3Mammal Review (2013) © 2013 The Mammal Society and John Wiley & Sons Ltd
food is not important in the wild boar diet. The consump-
tion of animal matter could be associated with a scarcity
of protein in the environment or could augment the
diet when other resources are scarce. For example, some
authors have indicated that, because acorns are deficient in
protein, wild boar may supplement an acorn diet with
animal matter (Barrett 1978, Belden & Frankenberger 1990,
Loggins et al. 2002). More research is needed to test this
hypothesis.
The importance of animal matter in terms of volume
varies (Fig. 2). In the native range, the volume of animal
matter is generally low, ranging from 1 to 16%. By contrast,
in the introduced range, values range from 2% to more than
33%, two times more than in the native range (Fig. 2,
Appendix S2). Animal items in both ranges include
mammals (Taylor & Hellgren 1997, Taylor & Uvalde 1999,
Skewes et al. 2007, Wilcox & Van Vuren 2009), birds
(Challies 1975, Rudge 1976, Herrero et al. 2004, Desbiez
2007, Skewes et al. 2007, Giménez-Anaya et al. 2008, Wilcox
& Van Vuren 2009), amphibians and reptiles (Jolley
et al. 2010), insects (Baber & Coblentz 1987, Thomson &
Challies 1988, Eriksson & Petrov 1995, Taylor & Hellgren
1997, Herrero et al. 2004), earthworms (Challies 1975,
Genov 1981a, Thomson & Challies 1988, Asahi 1995,
Fournier-Chambrillon et al. 1995, Baubet et al. 2004), snails
(Howe et al. 1981, Irizar et al. 2004, Herrero et al. 2005,
2006), and crustaceans (Giménez-Anaya et al. 2008).
Furthermore, wild boars may select a few items in large
numbers. For example, Wilcox and Van Vuren (2009) found
in the USA that California voles Microtus californicus
were the dominant prey species, totalling 109 individuals
and occurring in more than one-third of all stomachs
(104 samples). The prevalence of multiple vertebrates per
stomach suggested that they are not eaten only occasionally
(Wilcox & Van Vuren 2009). Although the bulk of animal
matter is usually composed of birds and mammals, the
presence of invertebrates (such as myriapods, insect larvae
and snails), especially earthworms, is remarkable in the
native and introduced range, and they are probably
eaten because of their high protein content (Wood &
Roark 1980, Genov 1981b, Thomson & Challies 1988,
Fournier-Chambrillon et al. 1995, Massei et al. 1996, Baubet
et al. 2004, Irizar et al. 2004).
Predator or scavenger?
Scavenging is a widespread phenomenon in vertebrate
animal communities. In particular, facultative scavenging
is common (DeVault et al. 2003, Selva et al. 2003). Wild
boars can be predators that opportunistically consume
carrion (facultative scavengers, Wilson & Wolkovich 2011),
although the overall relative proportion of scavenged vs.
preyed-upon vertebrate foods in wild boar diets is fre-
quently unknown (Taylor & Hellgren 1997, Taylor & Uvalde
1999) because it is often impossible to know whether an
animal was killed or ingested as carrion (Wood & Roark
1980).
In the introduced range, wild boars search for prey,
and most vertebrates found in stomachs are taken alive
(Wilcox & Van Vuren 2009). Prey include rodents, deer,
birds, snakes and frogs (Schneider 1975, Taylor & Hellgren
1997, Rollins & Carroll 2001, Skewes et al. 2007, Wilcox &
Van Vuren 2009, Jolley et al. 2010), as well as livestock
(Pavlov et al. 1981, Pavlov & Hone 1982, Choquenot et al.
1997). This predatory behaviour seems to be more severe on
islands where a variety of species is affected (Challies 1975,
Coblentz & Baber 1987, Cruz & Cruz 1987). However, some
researchers emphasize the importance of carrion, such as
carcasses of cows, brushtail possums Trichosurus vulpecula
and deer because it comprises a major portion of the animal
matter in the diet (Rudge 1976, Everitt & Alaniz 1980,
Thomson & Challies 1988, Desbiez 2007). Additionally, it is
believed that carrion cannibalism is common (Coblentz &
Baber 1987, Thomson & Challies 1988, Taylor & Hellgren
1997). In the native range, Selva (2004) found that the
wild boar, usually acting in groups, is one of the most
important scavengers in the forests of eastern Poland.
Likewise, in Spain, wild boars eat carrion of the European
roe deer Capreolus capreous and badger Meles meles (Sáenz
de Buruaga 1995, Herrero et al. 2005), and are predators
of ground-nesting birds (Nyenhuis 1991, Keuling 2007,
Giménez-Anaya et al. 2008) and amphibians (Carretero &
Rosell 1999).
Other food items
Wild boar diet often contains other uncommon food items
at low frequency and volume (1–7% of volume, Appen-
dix S2). These items include biological material such as
algae, fungi and garbage, as well as inorganic material
including plastic and stones.
In the native range, fungi are present in the diet occasion-
ally and are generally reported in low frequency and
volume (Genov 1981a, Groot Bruinderink et al. 1994,
Sáenz de Buruaga 1995, Baubet et al. 2004). However,
Fournier-Chambrillon et al. (1995) found a high frequency
of fungi, and Hohmann and Huckschlag (2005) found
a high proportion by weight of hart’s truffle Elaphomyces
granulatus. Inorganic items such as stones are regularly
ingested by wild boar, but in low proportion and perhaps
accidentally (Sáenz de Buruaga 1995).
In the introduced range, there are very few records of
the consumption of fungi, but overall fungus consumption
is significantly greater than in the native range (Fig. 2). In
Chile, Skewes et al. (2007) found that fungi are common in
stomachs (65%, mainly hypogeous forms). Similarly, Wood
A review of wild boar Sus scrofa diet S. A. Ballari and M. N. Barrios-García
4Mammal Review (2013) © 2013 The Mammal Society and John Wiley & Sons Ltd
and Roark (1980) in the USA found fungi during all seasons
and at relatively high frequencies, and in New Zealand, there
are records of the presence of toadstools (Challies 1975). In
New Zealand, two species of seaweed have also been found
in wild boar stomachs (Challies 1975, Chimera et al. 1995).
Items such as garbage and stones are not common in wild
boar diets in the introduced range (Henry & Conley 1972,
Taylor & Hellgren 1997).
Effects of wild boars on conservation and
endangered species
Wild boars frequently consume endangered or keystone
species; however, because estimates of population abun-
dance are unavailable for many species, the impact such
predation might have is unknown (Baber & Coblentz 1987,
Chimera et al. 1995). Ground-nesting birds are one of
the groups most affected by predation and nest destruc-
tion (Challies 1975, Opermanis et al. 2001, Herrero et al.
2004, Skewes et al. 2007, Giménez-Anaya et al. 2008). In
the native range, eggs and young of the purple gallinule
Porphyrio porphyrio in Spain are part of the wild boar’s diet
(Herrero et al. 2004, Giménez-Anaya et al. 2008), whereas in
the UK, Purger and Meszaros (2006) found that the wild
boar could be the main cause of loss of nests of ferruginous
ducks Aythya nyroca. In the introduced range, the yellow-
eyed penguin Megadyptes antipodes and the Auckland Island
prion Pachyptila desolata are two of the species most com-
monly consumed by the wild boar (Challies 1975). Skewes
et al. (2007) in Chile emphasize the high frequency of
endemic birds Scelorchilus rubecula and Pteroptochos tarnii
in wild boar stomachs.
Predation on reptiles has been reported in the Galápagos
(Ecuador), where the reproductive success of the green sea
turtle Chelonia myda and the giant land tortoise Geochelone
elephantop is severely reduced by the wild boar (MacFarland
et al. 1974, Coblentz & Baber 1987), as well as in Australia,
where predation by the wild boar is reducing the survival
of the northern snake-necked turtle Chelodina rugosa
(Fordham et al. 2006). Predation on amphibians has also
been reported in the introduced range, where wild boars
threaten eastern spadefoot toad Scaphiopus holbrookii popu-
lations (Jolley et al. 2010), and in the native range, where
vulnerable Salamandra salamandra are eaten (Irizar et al.
2004). Overall, it is expected that as wild boar populations
continue to grow and spread, threats to native wildlife will
also increase (Massei & Genov 2004).
Supplemental feeding and
agricultural damage
Wild boars are considered an agricultural pest in many
countries because of their preference for crops and because
their feeding behaviour can severely damage crops
(Fournier-Chambrillon et al. 1995, Hahn & Eisfeld 1998,
Herrero & Fernández de Luco 2003, Schley & Roper 2003,
Chauhan et al. 2009). Agricultural products are important
components of wild boar diet in western Europe (Schley &
Roper 2003), where food selection varies depending on
the occurrence of different crops or by positive selection
of certain crops over others (Genov 1981a, Schley & Roper
2003, Schley et al. 2008).
In their native range, wild boars depend heavily on agri-
cultural products and are well adapted to crop changes
(Schley & Roper 2003, Herrero et al. 2006). For example,
Herrero et al. (2006) reported that agricultural crops com-
prise almost 90% of the volume of the stomach contents
of wild boars. Agricultural plants in the Mediterranean
are consumed year-round, but primarily during summer
and autumn when their nutritional value is highest (Genov
1981a, Herrero et al. 2006, Cellina 2008, Giménez-Anaya
et al. 2008) or when the availability of natural foods
becomes unpredictable (Fournier-Chambrillon et al. 1995).
Furthermore, cultivated crops such as maize Zea mays (in
winter), oats Avena sativa (autumn and winter), rye Secale
cereale (winter), wheat Triticum spp. (winter), sugar beet
Beta vulgaris (autumn and winter), rice Oryza spp., barley
Hordeum vulgare, alfalfa Medicago sativa,sorghumSorghum
spp. and potatoes Solanum tuberosum (spring) are used by
wild boars (Genov 1981a, Herrero et al. 2006, Madsen et al.
2010).
In the introduced range, wild boars cause crop damage,
but it is reported less often than in the native range. In the
USA, wild boars consume large quantities of crops (wheat,
sorghum, barley, oilseeds, sugar cane Saccharum spp., oats
and maize) and tree seedlings (Lipscomb 1989, Mayer et al.
2000), causing serious damage (Seward et al. 2004). Fur-
thermore, wild boars cause economic losses by preying on
livestock such as newborn lambs Ovis aries and goats Capra
hircus (Moulk 1954, Rowley 1970, Pavlov et al. 1981,
Beach 1993) as well as game birds such as bobwhite quail
Colinus virginianus, woodcock Scolopax rusticola, capercail-
lie Tetrao urogallus and hazel grouse Bonasa bonasia
(Nyenhuis 1991, Tolleson et al. 1995, Saniga 2002, Schley &
Roper 2003).
Supplemental feeding consists of providing additional
food for wild animals for different purposes: dissuasive
feeding, baiting, massive feeding and vaccination among
others (Cellina 2008). There is speculation about the role of
supplemental food in the wild boar diet; it can attract wild
boars to hunting grounds or prevent crop damage, but it
may also help maintain wild boar populations when natural
resources are scarce. Indeed, some authors working in the
native range found that supplemental food comprises
more of the diet than some natural resources. For example,
Baubet et al. (2004) in the French Alps found that maize
S. A. Ballari and M. N. Barrios-García A review of wild boar Sus scrofa diet
5Mammal Review (2013) © 2013 The Mammal Society and John Wiley & Sons Ltd
(8%) is more important than humus (6%), forest fruits
(7%), animal matter (1%) and fungi (1%). Hahn and
Eisfeld (1998) found that supplemental food (mainly maize)
plays a key role throughout the year, and Cellina (2008)
reported that supplemental food constituted up to 55% of
the stomach contents. Similarly, Fournier-Chambrillon et al.
(1995) found that maize can account for one-third of the
annual diet and is eaten constantly throughout the year
except in winter. In contrast, in the introduced range, there
are no accurate records of the importance of supplemental
food in wild boar diets.
Factors affecting food selection
Several factors determine what food resources wild boars
use, and these can be grouped into four categories relating
to: food availability, energy requirements, seasonal varia-
tions and geographical variations.
Several authors agree that wild boar diet is determined by
food availability and energetic requirements (Diong 1982,
Fournier-Chambrillon et al. 1995, Massei et al. 1996, Schley
& Roper 2003, Geisser & Reyer 2004, Keuling 2007, Cellina
2008, Schley et al. 2008, Cuevas et al. 2013). For example,
Massei et al. (1996), in a Mediterranean coastal area, found
strong dependence on energy-rich food throughout the
range, irrespective of the habitat and latitude. Moreover,
they found that wild boar diet depends on the availability of
food items which are not necessarily related to seasons, and
they suggested that season could not be used to predict wild
boar diet. In Europe, when supplementary food or crops are
available, wild boars may modify their behaviour (e.g. dis-
persion, home range size) and distort their regular diet (e.g.
when mast is available), which may give an inaccurate
impression of their food selection (Eisfeld & Hahn 1998,
Schley & Roper 2003, Keuling 2007, Linderoth 2010). In the
introduced range, food availability and energy requirements
are also reported as important factors that determine diet.
For example, the availability of fruits has been reported as a
key resource of the diet of the wild boar in environments
such as rainforests and islands (Baber & Coblentz 1987,
Desbiez 2007).
Several authors showed that food selection varies with
seasons and geographical location (Challies 1975, Genov
1981a, Thomson & Challies 1988, Taylor & Hellgren 1997,
Baubet et al. 2004, Herrero et al. 2004, Hafeez et al. 2011).
For example, rooting is used when above-ground resources
are scarce (e.g. in winter and early spring; Scott 1973,
Barrett 1978, Baron 1982). In the native range, above-
ground plant parts are important in the spring when new
shoots of herbs are most luxuriant (Baubet et al. 2004).
Fruits are consumed throughout the year but more pre-
dominantly in summer (Baubet et al. 2004, Herrero et al.
2004). In Europe, wild boars consume a large number
of agricultural food items, particularly in summer and
autumn (Briedermann 1976, Genov 1981a, Hahn & Eisfeld
1998, Wilson 2004, Herrero et al. 2006, Cellina 2008,
Giménez-Anaya et al. 2008). Earthworms are also consumed
year-round, but consumption decreases significantly in the
winter months because of the snow cover (Genov 1981a,
Baubet et al. 2004). In the introduced range, above-ground
vegetable parts are consumed mostly in spring when grasses
sprout and are tender (Wood & Roark 1980, Taylor &
Hellgren 1997). Fruits are consumed throughout most of
the year except in spring (Wood & Roark 1980, Baber &
Coblentz 1987, Thomson & Challies 1988, Taylor &
Hellgren 1997), and, as in Europe, acorns are one of
the main foods during winter and autumn (Scott 1973,
Everitt & Alaniz 1980, Wood & Roark 1980, Loggins et al.
2002, Solís-Cámara et al. 2008).
In both native and introduced ranges, geographical varia-
tion represented mainly by altitudinal gradients and differ-
ences in precipitation may also determine some aspects
of food selection by the wild boar. For example, consump-
tion of animal matter may depend on altitude (Challies
1975, Baubet et al. 2004), and pastures may be avoided in
abnormally dry years (Everitt & Alaniz 1980).
Age and sex differences
A few records show dietary differences between ages and
sexes of wild boars. In the native range, Dardaillon (1986)
and Groot Bruinderink and Hazebroek (1996) reported a
greater proportion of animal matter and greater diversity of
food in juveniles than in yearlings and adults. Also, yearlings
and adults eat larger proportions of rice and below-ground
plant parts than do juveniles (Dardaillon 1986). These dif-
ferences between age classes were attributed to different
nutritional requirements or food availability (Dardaillon
1986). In the introduced range, Wilcox and Van Vuren
(2009) found that predation of vertebrates is more pro-
nounced in females than in males. Protein deficiency for
females facing the physiological cost of reproduction is
likely to be an important factor influencing predation on
vertebrates (Wilcox & Van Vuren 2009). However, most of
the reviewed studies showed no differences between age
and sex in both the native and introduced ranges (Wood &
Roark 1980, Durio et al. 1995, Loggins et al. 2002, Adkins &
Harveson 2006, Skewes et al. 2007).
CONCLUSION
Wild boars are generalist feeders with a highly plastic
diet that contributes to their wide geographical distribu-
tion (Barrios-Garcia & Ballari 2012, Baubet et al. 2004,
Herrero et al. 2006, Nogueira-Filho et al. 2009). In this
review, we found significant differences in the diets of wild
A review of wild boar Sus scrofa diet S. A. Ballari and M. N. Barrios-García
6Mammal Review (2013) © 2013 The Mammal Society and John Wiley & Sons Ltd
boars in their native and introduced ranges, though feeding
behaviours including browsing and grazing, rooting, and
preying seem to be similar in both ranges. We identified
four factors that influence food selection: food availability,
energy requirements, seasonal variation and geographical
variation. This information in combination with knowledge
of seasonal patterns of space and habitat use may help
inform the design of management plans.
Animal matter and fungi were eaten in greater propor-
tions in the introduced range than in the native range,
whereas the opposite occurred with plant matter. This
pattern might be explained partly by evolution. In the native
range, animal species co-evolved with wild boars over thou-
sands of years and developed strategies to avoid competi-
tion or predation. By contrast, in the introduced range,
animal species are not adapted to the presence and feeding
habits of wild boars and may therefore be more susceptible
to predation. Similarly, plants in the native range may be
adapted to the feeding behaviour of wild boars (rooting) for
their establishment and development. Indeed, Welander
(1995) showed that in Sweden, rooting enhances plant
diversity and richness. Although rooting in the introduced
range could replace suppressed natural events (e.g. wildfires;
Kotanen 1995) or extinct ecological equivalents (e.g. Ursus
arctos in California; Sweitzer & Van Vuren 2002), most
studies show negative effects of rooting on plant species
(Bratton 1975, Challies 1975, Singer et al. 1984, Hone 2002,
Tierney & Cushman 2006), suggesting that plants are not
adapted to wild boar disturbance.
As well as seasonal and geographic variation, energy
requirements and food availability are major factors influ-
encing wild boar diet in the introduced and native range.
Energy requirements may drive wild boar behaviour and
reproduction. For example, protein is essential in wild boar
diet, and a deficiency can trigger higher animal predation
rates, particularly in females facing the physiological cost of
reproduction (Wilcox & Van Vuren 2009). Food availability
is determined by environmental parameters (e.g. mast and
climate) as well as by human activities (e.g. supplemental
feeding and agricultural crops). Nevertheless, wild boars
seem to adapt their diet to whatever is available (Challies
1975, Wood & Roark 1980, Cellina 2008). For example, wild
boars rely strongly on acorns in good mast years but diver-
sify their diet during poor mast years (Briedermann 1976,
Fournier-Chambrillon et al. 1995, Massei et al. 1996). Avail-
ability not only influences the diet and feeding habits of
wild boar but may also alter other features such as popula-
tion dynamics, habitat use, dispersal, reproduction and
interactions with other species (Massei et al. 1996, Bieber &
Ruf 2005). For example, some authors suggested that under
food scarcity, resource competition may occur between the
wild boar and other mammals (Wood & Roark 1980, Massei
et al. 1996).
Dietary studies should be more rigorous and consistent
across ranges to allow better comparisons. The implications
of some studies on wild boar diet should be treated with
caution because of low sample sizes (Schley & Roper 2003)
or because they are limited to certain times of the year. Fur-
thermore, the frequency or volume of certain food items in
the diet could be underestimated because the analysis of
faeces may be less accurate than the evaluation of stomach
contents, in which foods are preserved better. Moreover, the
fast digestion of soft tissues (4–5 hours; Guerin et al. 2001)
may result in underestimated volumes. Finally, Wood and
Roark (1980) found that the use of some woody plants
may be underestimated, as wild boars may chew the roots,
swallow the sap and starches, and reject the woody tissue.
The quality of wild boar diet studies could be improved
by: (i) increasing the number of samples (many studies
reported results based on fewer than 10 samples); (ii)
reporting both frequency and volume values for food items;
and (iii) assessing seasonal differences in wild boar diet
based on food availability.
The effect of an invasive species can largely be inferred by
its trophic position in the community (Skewes et al. 2007).
Therefore, understanding what wild boars eat and how,
when and where they feed is critical to the delineation of
management and control plans in both ranges. Our findings
suggest that animal species in the introduced range are at
greater risk, both by virtue of being naïve and because they
are consumed in a greater proportion than in the native
range. A detailed study of diet could provide key informa-
tion such as target species and susceptible habitats on which
management efforts should focus.
ACKNOWLEDGMENTS
We thank Mariano Rodriguez-Cabal for assistance with the
test of effect sizes, and Daniel Simberloff and two anony-
mous reviewers for comments that improved the quality of
the manuscript.
REFERENCES
Adkins RN, Harveson LA (2006) Summer diets of feral hogs in
the Davis Mountains, Texas. The Southwestern Naturalist 51:
578–580.
Asahi M (1995) Stomach contents of Japanese wild boar in
winter. Journal of Mountain Ecology 3: 184–185.
Baber DW, Coblentz BE (1987) Diet, nutrition, and conception
in feral pigs on Santa Catalina Island. Journal of Wildlife
Management 51: 306–317.
Baron J (1982) Effects of feral hogs (Sus scrofa)onthe
vegetation of Horn Island, Mississippi. American Midland
Naturalist 107: 202–205.
S. A. Ballari and M. N. Barrios-García A review of wild boar Sus scrofa diet
7Mammal Review (2013) © 2013 The Mammal Society and John Wiley & Sons Ltd
Barrett RH (1978) The feral hog on the Dye Creek Ranch,
California. Hilgardia 46: 283–355.
Barrios-Garcia MN, Ballari SA (2012) Impact of wild boar (Sus
scrofa) in its introduced and native range: a review. Biological
Invasions 14: 2283–2300.
Baubet E, Bonenfant C, Brandt S (2004) Diet of the wild boar in
the French Alps. Galemys 16: 99–111.
Beach R (1993) Depredation problems involving feral hogs.
In: Hanselka CW, Cadenhead JF (eds) Feral Swine: A
Compendium for Resource Managers, 67–75. Texas Agricultural
Extension Service, Texas Animal Damage Control Service,
Texas Parks and Wildlife Department, Texas, USA.
Belden RC, Frankenberger WB (1990) Biology of a feral hog
population in south central Florida. Proceedings of the Annual
Conference of the Southeastern Association of Fish and Wildlife
Agencies: 231–242.
Bieber C, Ruf T (2005) Population dynamics in wild boar Sus
scrofa: ecology, elasticity of growth rate and implications for
the management of pulsed resource consumers. Journal of
Applied Ecology 42: 1203–1213.
Bratton SP (1975) The effect of the European wild boar, Sus
scrofa, on gray beech forest in the Great Smoky Mountains.
Ecology 56: 1356–1366.
Briedermann L (1976) Ergebnisse einer Inhaltsanalyse von 665
Wildschweinmägen. Zoologische Garten 46: 157–185.
Bueno C, Reiné R, Alados C, Gómez-García D (2011) Effects of
large wild boar disturbances on alpine soil seed banks. Basic
and Applied Ecology 12: 125–133.
Campos CM, Ojeda RA (1997) Dispersal and germination of
Prosopis flexuosa (Fabaceae) seeds by desert mammals in
Argentina. Journal of Arid Environments 35: 707–714.
Carretero MA, Rosell C (1999) Salamandra salamandra
(fire salamandra) predation. Herpetological Review
30: 161.
Cellina S (2008) Effects of Supplemental Feeding on the Body
Condition and Reproductive State of Wild Boar (Sus scrofa) in
Luxembourg. PhD thesis, University of Sussex, UK.
Challies CN (1975) Feral pigs (Sus scrofa) on Auckland Island:
status, and effects on vegetation and nesting sea birds.
New Zealand Journal of Zoology 2: 479–490.
Chauhan N, Kuldeep SB, Kumar D (2009) Human wild pig
conflict in selected states in India and mitigation strategies.
Acta Silvatica et Lignaria Hungarica 5: 189–197.
Chimera C, Coleman MC, Parkes JP (1995) Diet of feral goats
and feral pigs on Auckland Island, New Zealand. New Zealand
Journal of Ecology 19: 203–207.
Choquenot D, Lukins B, Curran G (1997) Assessing lamb
predation by feral pigs in Australia’s semi-arid rangelands.
Journal of Applied Ecology 34: 1445–1454.
Coblentz BE, Baber DW (1987) Biology and control of feral pigs
on Isla Santiago, Galapagos, Ecuador. Journal of Applied
Ecology 24: 403–418.
Cruz JB, Cruz F (1987) Conservation of the dark-rumped petrel
(Pterodroma phaeopygia) in the Galapagos Islands, Ecuador.
Biological Conservation 42: 303–311.
Cuevas MF, Mastrantonio L, Ojeda RA, Jaksic FM (2012) Effects
of wild boar disturbance on vegetation and soil properties in
the Monte Desert, Argentina. Mammalian Biology 77:
299–306.
Cuevas MF, Novillo A, Campos C, Dacar MA, Ojeda RA (2010)
Food habits and impact of rooting behavior of the invasive
wild boar, Sus scrofa, in a protected area of the Monte Desert,
Argentina. Journal of Arid Environments 74: 1582–1585.
Cuevas MF, Ojeda RA, Dacar MA, Jaksic FM (2013) Seasonal
variation in feeding habits and diet selection by wild boars in
a semi-arid environment of Argentina. Acta Theriologica 58:
63–72.
Dardaillon M (1986) Seasonal variations in habitat selection and
spatial distribution of wild boar (Sus scrofa) in the Camargue,
Southern France. Behavioural Processes 13: 251–268.
Desbiez ALJ (2007) Wildlife Conservation in the Pantanal:
Habitat Alteration, Invasive Species and Bushmeat Hunting.
PhD thesis, University of Kent, Canterbury, UK.
DeVault TL, Rhodes JOE, Shivik JA (2003) Scavenging by
vertebrates: behavioral, ecological, and evolutionary
perspectives on an important energy transfer pathway in
terrestrial ecosystems. Oikos 102: 225–234.
Diong CH (1982) Population Biology and Management of the
Feral Pig (Sus scrofa L.) in Kipahulu Valley, Maui. PhD thesis,
University of Hawaii, Honolulu, USA.
Dovrat G, Perevolotsky A, Ne’eman G (2012) Wild boars as
seed dispersal agents of exotic plants from agricultural lands
to conservation areas. Journal of Arid Environments 78:
49–54.
Durio P, Fogliato D, Perrone A, Tessarin N (1995) The Autumn
diet of the wild boar (Sus scrofa) in an alpine valley.
Preliminary results. Journal of Mountain Ecology 3: 180–183.
Eisfeld D, Hahn N (1998) Raumnutzung und Ernährungsbasis
von Schwarzwild. Abschlussbericht. Arbeitsbereich
Wildökologie und Jagdwirtschaft, Forstzoologisches Institut,
Universität Freiburg.
Eriksson O, Petrov M (1995) Wild boars (SusscrofascrofaL.)
around Chernobyl, Ukraine. Seasonal feed choice in an
environment under transition: a baseline study. Journal of
Mountain Ecology 3: 171–173.
Everitt J, Alaniz M (1980) Fall and winter diets of feral pigs in
south Texas. Journal of Range Management 33: 126–129.
Fordham D, Georges A, Corey B, Brook BW (2006) Feral pig
predation threatens the indigenous harvest and local
persistence of snake-necked turtles in northern Australia.
Biological Conservation 133: 379–388.
Fournier-Chambrillon C, Maillard D, Fournier P (1995) Diet of
wild boar (Sus scrofa L.) inhabiting the Monpellier garrigue.
Journal of Mountain Ecology 3: 174–179.
Geisser H, Reyer HU (2004) Efficacy of hunting, feeding, and
fencing to reduce crop damage by wild boars. Journal of
Wildlife Management 68: 939–946.
Genov P (1981a) Food composition of wild boar in
north-eastern and western Poland. Acta Theriologica 26:
185–205.
A review of wild boar Sus scrofa diet S. A. Ballari and M. N. Barrios-García
8Mammal Review (2013) © 2013 The Mammal Society and John Wiley & Sons Ltd
Genov P (1981b) Significance of natural biocenoses and
agrocenoses as the source of food for wild boar
(Sus scrofa L.). Ekologia Polska 29: 117–138.
Giffin J (1978) Ecology of the feral pig on the island of Hawaii.
State of Hawaii, Department of Land and Natural Resources,
Division of Fish and Game.
Giménez-Anaya A, Herrero J, Rosell C, Couto S, García-Serrano
A (2008) Food habits of wild boars (Sus scrofa)ina
Mediterranean coastal wetland. Wetlands 28: 197–203.
Groot Bruinderink G, Hazebroek E (1996) Wild boar (Sus scrofa
scrofa L.) rooting and forest regeneration on podzolic soils
in the Netherlands. Forest Ecology and Management 88:
71–80.
Groot Bruinderink G, Hazebroek E, Van Der Voot H (1994)
Diet and condition of wild boar, Susscrofascrofa, without
supplementary feeding. Journal of Zoology 233: 631–648.
Guerin S, Ramonet Y, LeCloarec J, Meunier-Salaün M,
Bourguet P, Malbert C (2001) Changes in intragastric meal
distribution are better predictors of gastric emptying rate in
conscious pigs than are meal viscosity or dietary fibre
concentration. British Journal of Nutrition 85: 343–350.
Hafeez S, Abbas M, Khan ZH, Rehman E (2011) Preliminary
analysis of the diet of wild boar (Sus scrofa L., 1758) in
Islamabad, Pakistan. Turkish Journal of Zoology 35:
115–118.
Hahn N, Eisfeld D (1998) Diet and habitat use of wild boar (Sus
scrofa)inSWGermany.Gibier Faune Sauvage 15: 595–606.
Hedges LV, Gurevitch J, Curtis PS (1999) The meta-analysis of
response ratios in experimental ecology. Ecology 80:
1150–1156.
Heinken T, Raudnitschka D (2002) Do wild ungulates
contribute to the dispersal of vascular plants in central
European forests by epizoochory? A case study in NE
Germany. Forstwissenschaftliches Centralblatt 121: 179–194.
Henry VG, Conley RH (1972) Fall foods of European wild hogs
in the southern Appalachians. Journal of Wildlife Management
36: 854–860.
Herrero J, Couto S, Rosell C, Arias P (2004) Preliminary data on
the diet of wild boar living in a Mediterranean coastal
wetland. Wild boar research 2002: 115–123.
Herrero J, Fernández de Luco D (2003) Wild boars (Sus scrofa
L.) in Uruguay: scavengers or predators? Mammalia 67:
485–491.
Herrero J, García-Serrano A, Couto S, Ortuño VM,
García-González R (2006) Diet of wild boar Sus scrofa L. and
crop damage in an intensive agroecosystem. European Journal
of Wildlife Research 52: 245–250.
Herrero J, Irizar I, Laskurain NA, García-Serrano A,
García-González R (2005) Fruits and roots: wild boar foods
during the cold season in the southwestern Pyrenees. Italian
Journal of Zoology 72: 49–52.
Hohmann U, Huckschlag D (2005) Investigations on the
radiocaesium contamination of wild boar (Sus scrofa) meat in
Rhineland-Palatinate: a stomach content analysis. European
Journal of Wildlife Research 51: 263–270.
Hone J (2002) Feral pigs in Namadgi National Park, Australia:
dynamics, impacts and management. Biological Conservation
105: 231–242.
Howe TD, Singer FJ, Ackerman BB (1981) Forage relationships
of european wild boar invading northern hardwood forest.
Journal of Wildlife Management 45: 748–754.
Irizar I, Laskurain NA, Herrero J (2004) Wild boar frugivory in
the Atlantic Basque Country. Galemys 16: 125–133.
Jolley DB, Ditchkoff SS, Sparklin BD, Hanson LB, Mitchell MS,
Grand JB (2010) Estimate of herpetofauna depredation by a
population of wild pigs. Journal of Mammalogy 91: 519–524.
Keuling O (2007) Sauen als Beutegreifer-Welchen Einfluss kann
Schwarzwild auf andere Tierarten ausüben? 13.
Österreichische Jägertagung, 13. und 14. Februar 2007
Raumberg-Gumpenstein, Höhere Bundeslehr-und
Forschungsanstalt für Landwirtschaft, Irdning 45–50.
Kotanen PM (1995) Responses of vegetation to a changing
regime of disturbance: effects of feral pigs in a Californian
coastal prairie. Ecography 18: 190–199.
Linderoth P (2010) Energieversorgung und Reproduktion einer
Schwarzwildpopulation. In: Pegel M, Linderoth P (eds)
Schwarzwildseminar Schwäbische Bauernschule Bad Waldsee,
6–12. Bildungs- und Wissenszentrum Aulendorf –
Viehhaltung, Grünlandwirtschaft, Wild, Fischerei –
Wildforschungsstelle Aulendorf, Aulendorf, Austria.
Lipscomb DJ (1989) Impacts of feral hogs on longleaf pine
regeneration. Southern Journal of Applied Forestry 13:
177–181.
Loggins RE, Wilcox JT, Van Vuren D, Sweitzer RA (2002)
Seasonal diets of wild pigs in oak woodlands of the central
coast region of California. California Fish and Game 88:
28–34.
MacFarland CG, Villa J, Toro B (1974) The Galápagos giant
tortoises (Geochelone elephantopus). Part I: status of the
surviving populations. Biological Conservation 6: 118–133.
Madsen P, Gamborg C, Lund DH, Thorsen BJ,
Raulund-Rasmussen K (2010) Erfaringer med
vildsvineforvaltning i Sverige og Tyskland. 8779034772,
Skov og Landskab, LIFE, Københavns Universitet.
Massei G, Genov P (2004) The environmental impact of wild
boar. Galemys 16: 135–145.
Massei G, Genov P, Staines B (1996) Diet, food availability and
reproduction of wild boar in a Mediterranean coastal area.
Acta Theriologica 41: 307–320.
Matías L, Zamora R, Mendoza I, Hódar JA (2010) Seed dispersal
patterns by large frugivorous mammals in a degraded mosaic
landscape. Restoration Ecology 18: 619–627.
Mayer JJ, Nelson EA, Wike LD (2000) Selective depredation of
planted hardwood seedlings by wild pigs in a wetland
restoration area. Ecological Engineering 15: S79–S85.
Moulk G (1954) Observations on mortality amongst lambs in
Queensland. Australian Veterinary Journal 30: 153–171.
Nogueira-Filho SLG, Nogueira SSC, Fragoso JMV (2009)
Ecological impacts of feral pigs in the Hawaiian Islands.
Biodiversity and Conservation 18: 3685–3686.
S. A. Ballari and M. N. Barrios-García A review of wild boar Sus scrofa diet
9Mammal Review (2013) © 2013 The Mammal Society and John Wiley & Sons Ltd
Nyenhuis H (1991) Feindbeziehung zwischen Waldschnepfe
(Scolopax rusticola L.), Raubwild und Wildschwein (Sus scrofa
L.). Allgemeine Forst-und Jagd-Zeitung 162: 174–180.
O’Connor S-J, Kelly D (2012) Seed dispersal of matai
(Prumnopitys taxifolia) by feral pigs (Sus scrofa). New Zealand
Journal of Ecology 36: 228–231.
Opermanis O, Mednis A, Bauga I (2001) Duck nests and
predators: interaction, specialisation and possible
management. Wildlife Biology 7: 87–96.
Osenberg CW, Sarnelle O, Cooper SD, Holt RD (1999)
Resolving ecological questions through meta-analysis: goals,
metrics, and models. Ecology 80: 1105–1117.
Pavlov P, Edwards E (1995) Feral pig ecology in Cape
Tribulation National Park, North Queensland, Australia.
Journal of Mountain Ecology 3: 148–151.
Pavlov P, Hone J (1982) The behaviour of feral pigs, Sus scrofa,
in flocks of lambing ewes. Wildlife Research 9: 101–109.
Pavlov P, Hone J, Kilgour R, Pedersen H (1981) Predation by
feral pigs on Merino lambs at Nyngan. New South Wales.
Australian Journal of Experimental Agriculture and Animal
Husbandry 21: 570–574.
Purger JJ, Meszaros LA (2006) Possible effects of nest predation
on the breeding success of Ferruginous Ducks Aythya nyroca.
Bird Conservation International 16: 309–316.
Rollins D, Carroll JP (2001) Impacts of predation on northern
bobwhite and scaled quail. Wildlife Society Bulletin 29: 39–51.
Rosell C, Fernández-Llario P, Herrero J (2001) El jabalí (Sus
scrofa Linnaeus, 1758). Galemys 13: 1–25.
Rowley I (1970) Lamb predation in Australia: incidence,
predisposing conditions, and the identification of wounds.
Wildlife Research 15: 79–123.
Rudge M (1976) A note on the food of feral pigs (Sus scrofa)of
Auckland Island. Proceedings of the New Zealand Ecological
Society 23: 83–84.
Sáenz de Buruaga M (1995) Alimentación del jabalí (Sus scrofa
castilianus) en el norte de España. Ecología 9: 367–386.
Sanguinetti J, Kitzberger T (2010) Factors controlling seed
predation by rodents and non-native Sus scrofa in Araucaria
araucana forests: potential effects on seedling establishment.
Biological Invasions 12: 689–706.
Saniga M (2002) Nest loss and chick mortality in capercaillie
(Tetrao urogallus) and hazel grouse (Bonasa bonasia) in West
Carpathians. Folia Zoologica 51: 205–214.
Schley L, Dufrêne M, Krier A, Frantz AC (2008) Patterns of crop
damage by wild boar (Sus scrofa) in Luxembourg over a
10-year period. European Journal of Wildlife Research 54:
589–599.
Schley L, Roper TJ (2003) Diet of wild boar, Sus scrofa,in
Western Europe, with particular reference to consumption of
agricultural crops. Mammal Review 33: 43–56.
Schmidt M, Sommer K, Kriebitzsch WU, Ellenberg H, von
Oheimb G (2004) Dispersal of vascular plants by game in
northern Germany. Part I: roe deer (Capreolus capreolus) and
wild boar (Sus scrofa). European Journal of Forest Research 123:
167–176.
Schneider E (1975) Mäuse im Magen eines Wildschweines
(Sus scrofa L.). Zeitschrift für Jagdwissenschaft 21: 190–192.
Scott C (1973) Seasonal Food Habits of European Wild Hogs
(Sus scrofa) in the Great Smoky Mountains National Park. MSc
thesis, University of Tennessee, USA.
Selva N (2004) The Role of Scavenging in the Predator
Community of Białowiez˙a Primeval Forest (E Poland).
PhD thesis, University of Sevilla, Spain.
Selva N, Jedrzejewska B, Jedrzejewski W, Wajrak A (2003)
Scavenging on European bison carcasses in Bialowieza
primeval forest (eastern Poland). Ecoscience 10: 303–311.
Seward NW, VerCauteren KC, Witmer GW, Engeman RM
(2004) Feral swine impacts on agriculture and the
environment. Sheep & Goat Research Journal 19:
34–40.
Singer FJ, Swank WT, Clebsch EEC (1984) Effects of wild pig
rooting in a deciduous forest. Journal of Wildlife Management
48: 464–473.
Skewes O, Rodriguez R, Jaksic FM (2007) Trophic ecology of the
wild boar (Sus scrofa) in Chile. Revista Chilena De Historia
Natural 80: 295–307.
Solís-Cámara AB, Arnaud-Franco G, Álvarez-Cárdenas S,
Galina-Tessaro P, Montes-Sánchez JJ (2008) Evaluación de la
población de cerdos asilvestrados (Sus scrofa) y su impacto en
la Reserva de la Biosfera Sierra La Laguna, Baja California Sur,
México. Tropical Conservation Science 2: 173–188.
Spatz G, Mueller-Dombois D (1972) Succession patterns after
pig digging in grassland communities on Mauna Loa, Hawaii.
Honolulu (HI): Island Ecosystems IRP, U.S. International
Biological Program. International Biological Program
Technical Report, 15.
Sweitzer RA, Van Vuren DH (2002) Rooting and Foraging Effects
of Wild Pigs on Tree Regeneration and Acorn Survival in
California’s Oak Woodland Ecosystems. USDA Forest Service
General Technical Report: 219–231.
Taylor RB, Hellgren EC (1997) Diet of feral hogs in the
western South Texas Plains. The Southwestern Naturalist 42:
33–39.
Taylor RB, Uvalde T (1999) Seasonal diets and food habits of
feral swine. Pages 58–66 in Proceedings of the First National
Feral Swine Symposium, Ft. Worth, Texas, USA.
Thomson C, Challies C (1988) Diet of feral pigs in the
podocarp-tawa forests of the Urewera Ranges. New Zealand
Journal of Ecology 11: 73–78.
Tierney TA, Cushman JH (2006) Temporal changes in native
and exotic vegetation and soil characteristics following
disturbances by feral pigs in a California grassland. Biological
Invasions 8: 1073–1089.
Tolleson DR, Pinchak WE, Rollins D, Hunt LJ (1995) Feral hogs
in the rolling plains of Texas: perspectives, problems, and
potential. Pages 124–128 in Wildlife Damage Management,
Internet Center for Great Plains Wildlife Damage Control
Workshop Proceedings, University of Nebraska, Lincoln, USA.
Tucak Z (1996) Results of the investigations of the stomach
contents of 155 wild boar (Sus scrofa L.) in the unfenced
A review of wild boar Sus scrofa diet S. A. Ballari and M. N. Barrios-García
10 Mammal Review (2013) © 2013 The Mammal Society and John Wiley & Sons Ltd
portion of the forest hunting reserve Belje in Baranja.
Zeitschrift für Jagdwissenschaft 42: 165–172.
Welander J (1995) Are wild boars a future threat to the Swedish
flora? Journal of Mountain Ecology 3: 165–167.
Wiedemann S, Lutz B, Albrecht C, Kuehn R, Killermann B,
Einspanier R, Meyer HH (2009) Fate of genetically modified
maize and conventional rapeseed, and endozoochory in
wild boar (Sus scrofa). Zeitschrift für Säugetierkunde 74:
191–197.
Wilcox JT, Van Vuren DH (2009) Wild pigs as predators in
oak woodlands of California. Journal of Mammalogy 90:
114–118.
Wilson CJ (2004) Rooting damage to farmland in Dorset,
southern England, caused by feral wild boar Sus scrofa.
Mammal Review 34: 331–335.
Wilson EE, Wolkovich EM (2011) Scavenging: how carnivores
and carrion structure communities. Trends in Ecology &
Evolution 26: 129–135.
Wlazełko M, Łabudzki L (1992) Über die
Nahrungskomponenten und die trophische Stellung des
Schwarzwildes im Forschungsgebiet Zielonka. Zeitschrift für
Jagdwissenschaft 38: 81–87.
Wood GW, Roark DN (1980) Food habits of feral hogs in
coastal South Carolina. Journal of Wildlife Management 44:
506–511.
SUPPORTING INFORMATION
Additional supporting information may be found in the
online version of this article at the publisher’s web-site.
Appendix S1. References relevant to wild boar diet found
in the literature search.
Appendix S2. References used in this review to assess and
compare wild boar diet in the native and introduced range.
S. A. Ballari and M. N. Barrios-García A review of wild boar Sus scrofa diet
11Mammal Review (2013) © 2013 The Mammal Society and John Wiley & Sons Ltd
... Sus scrofa, as an omnivore, can adapt to a diverse diet, and the diet is also susceptible to change due to anthropogenic influences. Although wild boars have been observed to prey on insects, earthworms, frogs, and other small animals, a quantitative evaluation of the diet of wild boars revealed a strong dependence on plant food resources and a tendency toward herbivory (Studnitz et al., 2007;Ballari and Barrios-García, 2014). Similar food preferences have been observed in rewilded pigs that had been once domesticated (Signoret et al., 1975), and it is expected that similar preferences to be maintained in domesticated pigs. ...
... The estimated TP ter of the wild boars at these sites is 2.1 ± 0.1 and 2.1 ± 0.1, respectively, which is very slightly higher than the TP ter of sheep and goats at the same sites (2.0 ± 0.0 and 2.0 ± 0.1, respectively) (Itahashi et al., 2017(Itahashi et al., , 2021; Table 5 and Figure 4). Therefore, the diets of wild boars in the Neolithic period appear to have been highly dependent on plants, as previously assumed (Ballari and Barrios-García, 2014). However, the number of archeological sites at which the compound-specific nitrogen isotope compositions of S. scrofa (assumed to have been domesticated pigs) have been reported is limited throughout the Near East and Europe combined (Itahashi et al., 2018(Itahashi et al., , 2019Rey et al., 2022). ...
Article
Full-text available
The chemical analysis of animal bones from ancient sites has become a common approach in archeological research investigating animal utilization and domestication by past humans. Although several chemical indicators have been used to determine pig management practices in ancient societies, one indicator that can clarify human-animal relationships in the early stages of domestication is the change in the animal’s diet from its wild diet, which can be detected using isotope analysis of its bones. Omnivores, such as boars, are assumed to have shared foods with humans as their interaction increased, and a shift in the isotopic (carbon and nitrogen) compositions of their bone collagen toward humans are considered evidence of domestication. This approach has found evidence of early-stage pig management with human leftovers and feces in prehistoric East Asia, including in Neolithic China, Korea and Japan. However, in the Near East, one of the origins of animal domestication, even individual animals considered to be domesticated pigs according to zooarcheological data (such as morphological characteristics and mortality patterns) display isotopic compositions of bulk collagen that differ from those of humans but are close to those of herbivores. This result indicates that these pigs were fed special foods, such as legumes, rather than human leftovers or feces. However, the carbon and nitrogen isotopic compositions of the bulk collagen of herbivores found at the same sites showed huge variations, so the interpretation of the pigs’ diet is consequently unclear. In this study, a compound-specific nitrogen isotope analysis was used to clarify the pig diet and management strategies unique to the Neolithic Near East, Turkey and Syria, together with a carbon and nitrogen isotope analysis of bulk collagen. This study examines the diversity of pig management techniques in early agricultural societies and their relationship with the availability of other domestic animals and farming practices.
... However, some ungulates are omnivorous, such as wild boar, and consume belowground plant organs, fungi, invertebrates and soil organic matter (i.e. rooting, grubbing) [10]. Wild boar rooting behaviour consists of bioturbating the soil by disturbing the understory layer vegetation, pushing litter away or burying this organic material on the same spot [3,11,12]. ...
... Wild boar rooting activity consists of disturbing the understory layer vegetation, pushing litter and the bryophyte layer away or burying this organic material on the same spot. They consume seedlings, plant shoots, fruits, seeds, gastropods, batrachians and arthropods, which makes wild boar an omnivorous ungulate species [10,23,24]. Further, wild boar feed on soil organisms by excavating soil, and they consume roots, bulbs, hyphal networks, arthropod larvae and other soil fauna such as earthworms [20,25]. ...
Article
Full-text available
In the last few decades wild boar populations have expanded northwards, colonizing boreal forests. The soil disturbances caused by wild boar rooting may have an impact on soil organisms that play a key role in organic matter turnover. However, the impact of wild boar colonization on boreal forest ecosystems and soil organisms remains largely unknown. We investigated the effect of natural and simulated rooting on decomposer and predatory soil mites (total, adult and juvenile abundances; and adult–juvenile proportion). Our simulated rooting experiment aimed to disentangle the effects of (i) bioturbation due to soil mixing and (ii) removing organic material (wild boar food resources) on soil mites. Our results showed a decline in the abundance of adult soil mites in response to both natural and artificial rooting, while juvenile abundance and the relative proportion of adults and juveniles were not affected. The expansion of wild boar northwards and into new habitats has negative effects on soil decomposer abundances in boreal forests which may cascade through the soil food web ultimately affecting ecosystem processes. Our study also suggests that a combined use of natural and controlled experimental approaches is the way forward to reveal any subtle interaction between aboveground and belowground organisms and the ecosystem functions they drive.
... Pigs are a strongly invasive, gregarious and omnivorous generalist occurring in a wide variety of ecosystems and landscape types worldwide (McClure et al., 2015). Their diets are flexible and can include a variety of naturally occurring herbaceous vegetation and hard and soft mast (Quercus spp.; Ballari & Barrios-García, 2014). They also opportunistically consume vertebrate and non-vertebrate fauna when available (Ballari & Barrios-García, 2014). ...
... Their diets are flexible and can include a variety of naturally occurring herbaceous vegetation and hard and soft mast (Quercus spp.; Ballari & Barrios-García, 2014). They also opportunistically consume vertebrate and non-vertebrate fauna when available (Ballari & Barrios-García, 2014). Feral pigs also consume, trample and damage agricultural crops (e.g. ...
Article
Full-text available
1. The ability to predict animal space use patterns is a fundamental concern in changing environments. Such predictions require a detailed understanding of the movement mechanisms from which spatial distributions emerge. However, these are typically complex, multifaceted, and therefore difficult to uncover. 2. Here we provide a methodological framework for uncovering the movement mechanisms necessary for building predictive models of animal space use. Our procedure begins by parametrising a movement model of each individual in a population using step selection analysis, from which we build an individual‐based model (IBM) of interacting individuals, derive predicted broad‐scale space use patterns from the IBM, then compare the predicted and empirical patterns. Importantly, discrepancies between these predicted and empirical patterns are used to formulate new hypotheses about the drivers of animal movement decisions and thus iteratively improve the model’s predictive power. We demonstrate our method on a population of feral pigs in Mississippi, USA. 3. Our technique incorporates both social interactions between individuals and environmental drivers of movement. At each iteration of model construction, we were able to identify missing features to improve model prediction by analysing the IBM output. These include overuse‐avoidance effects of self‐attractive mechanisms (i.e. attraction to previously visited sites becomes repulsion if there have been multiple visits in quick succession), which were vital for ensuring predicted occurrence distributions do not become vanishingly small. 4. Overall, we have provided a general method for iteratively improving the predictive power of step selection models. This will enable future researchers to maximize the information obtained from step selection analyses and to highlight potentially missing data for uncovering the drivers of movement decisions and emergent space use patterns. Ultimately, this provides a fundamental step towards the general aim of constructing predictive models of animal space use.
... It was suggested that competitively subordinate carnivores might be attracted to scat sites to estimate their proximity to and risk of encountering the dominant predator and/or to feed on undigested prey remains in scats (King et al. 2016;Wikenros et al. 2017). Large omnivorous species, such as wild boars (Sus scrofa) which occasionally feed on carcasses and prey remains (Ballari and Barrios-Garcia 2014;Focardi et al. 2017), may also use scats to feed on undigested prey remains therein. ...
Article
Full-text available
Many mammalian species communicate via olfactory communication placed at particular locations. The majority of these studies focused on intraspecific communication. More recently, studies have also investigated interspecific communication and recorded prey animals sniffing olfactory cues left by predators and predators investigating or counter-marking cues left by other predator species. The purpose of exchanging olfactory cues within a species community is little understood. Using a comparative study design, we investigated the behaviour of a mammalian community at cheetah marking trees and paired control trees using camera traps on Namibian farmland. We tested the predictions derived from hypotheses regarding the reasons for visits to the marking trees. Cheetah marking trees and control trees were visited 1101 times by 29 mammalian species (excluding cheetahs), with more species recorded at the marking trees than control trees. Two competitively subordinate carnivore species made more visiting and sniffing events, respectively, at cheetah marking trees than control trees, possibly to assess the time since cheetahs were in the area. Two opportunistic scavenger species sniffed more frequently at the marking trees than control trees, perhaps to feed on undigested prey remains in scats. One common prey species of cheetahs had fewer visiting events at the marking trees than control trees, likely to reduce encounters with cheetahs. Further, one species that is rarely preyed by cheetahs marked cheetah marking trees at the same frequency as control trees, suggesting it uses conspicuous sites rather for intraspecific than interspecific communication. Thus, trees used by cheetahs for marking also play an important role in olfactory communication for a variety of mammalian species.
... An omnivorous animal, it has a broad feeding niche with a diet including roots, seeds, fruits, seeds, invertebrates and carrion. Foraging wild boar rely on olfactory cues to search for food by grubbing or rooting in the upper layers of soils (Briedemann 1990, Ballari andBarrios-García, 2014). The species is normally active at dusk and at night (Lemel et al. 2003;Keuling et al. 2008;Ohashi et al. 2013), but when not disturbed it can also be active during the daytime (Podgórski et al. 2013). ...
Article
Full-text available
The features of the urban landscape encouraging large ungulates expansion are not known. However, prevalence and abundance of wild boar Sus scrofa has been steadily increasing over the years, and nowadays the species has become a recognized component of urban wildlife in many parts of its range. The aim of this work was to select habitat and human-related factors that could affect the probability of the species occurrence and constitute the honest indicators of the habitat suitability for this ungulate in the urban landscape. The data on the presence of grubbed patches of ground (an honest indicator of occurrence) were collected on randomly selected sample plots (N = 100) within the city of Kraków (Poland). We found that wild boar used 45% of the sample plots. Whereas the occupied plots were spatially concentrated, the habitat variables increasing the probability of the species occurring in the urban landscape were the presence of large patches of woodland remnants and large areas of semi-natural meadows. However, the study also revealed a negative relationship between the presence of the species and artificial lighting but a positive one with anthropogenic noise pollution. Our results indicate that the urban landscape consists of surrogate habitats for this large mammal but light and noise pollution may have contrasting effects on the species’ occurrence. This indicates that the influence of human-related factors on the attractiveness of natural vegetation remnants for wildlife is more complex than merely a limiting factor. This reveals high potential of light and noise pollution as indicators of the habitat suitability for ungulates in the urban landscape.
... Wild Suiformes are foraging animals with a diet consisting roughly 90% of plant-derived foods such as fruits, roots, leaves, and grasses. The relative amount of dietary fat is usually low (,10%;Leus 1994;Ballari and Barrios-García 2014;Souron et al. 2015), whereas in the swine industry additional fat is added to feed for a better performance (Lewis and Southern 2000). Fat-related OR duplications could be the consequence of adaptation to a high-fat Liu et al. · https://doi.org/10.1093/molbev/msac110 ...
Article
Full-text available
It is largely unknown how mammalian genomes evolve under rapid speciation and environmental adaptation. An excellent model for understanding fast evolution is provided by the genus Sus, which diverged relatively recently and lacks post-zygotic isolation. Here, we present a high-quality reference genome of the Visayan warty pig, which is specialized to a tropical island environment. Comparing the genome sequences and chromatin contact maps of the Visayan warty pig (Sus cebifrons) and domestic pig (Sus scrofa), we characterized the dynamics of chromosomal structure evolution during Sus speciation, revealing the similar chromosome conformation as the potential biological mechanism of frequent post-divergence hybridization among Suidae. We further investigated the different signatures of adaptive selection and domestication in Visayan warty pig and domestic pig with specific emphasize on the evolution of olfactory and gustatory genes, elucidating higher olfactory diversity in Visayan warty pig and positive and relaxed evolution of bitter and fat taste receptors, respectively, in domestic pig. Our comprehensive evolutionary and comparative genome analyses provide insight into the dynamics of genomes and how these change over relative short evolutionary times, as well as how these genomic differences encode for differences in the phenotypes.
... This finding concurs with that reported for older feral pigs, for which nearly 90% of their diet comprised vegetable matter (Ballari & Barrios-García, 2014). To the authors' knowledge, no literature data on diet selection in suckling feral piglets is available. ...
Article
Evaluation of the diet of the pig (Sus scrofa) in natural settings may provide new views on diet optimization for growth and development of commercially raised piglets under farm conditions. A field study was conducted to gain insight in the diet and stomach characteristics of feral piglets. Forty animals (body weight: 4.6 ± 1.37 kg) were collected from the Bahía Samborombón (Buenos Aires, Argentina). Stomachs were weighed after storage in formalin and the particle size distribution of their contents was determined by wet sieving. Diet items present in their stomachs were classified and their proportional weight and relative abundance was calculated. Based on their dentition, 5, 16 and 19 piglets were approximately 1, 3–6 and 6–16 weeks of age respectively. Vegetable matter (mainly ‘leaves and stems’) was predominantly present in 39 animals. It represented on average 83 ± 36.4% of total stomach contents by weight. The stomachs of 12 piglets contained curd and represented on average 16 ± 35.1% by weight. Other diet items were less abundant or absent. The proportion of stomach particles retained were 24%, 13%, 22%, 13% and 28% for sieves with mesh sizes of 2000, 1000, 420, 210 and <210 µm respectively. For comparison, we used data of farmed piglets of similar age and fed a nutrient‐dense, finely ground diet. Feral piglets' relative empty stomach weights increased with age (p < 0.050), whereas this was not the case for farmed piglets. Relative stomach contents weight increased significantly with age only for farmed piglets (p < 0.050). We infer from our data that feral suckling piglets consumed a variety of non‐milk items, mainly consisting of vegetable material with a coarse particle size from their first week in life onwards. Their diet is associated with an enhanced stomach development compared to those of farmed piglets.
... Primarily, however, human-wild boar interactions are framed as conflictual. Normatively represented as forest inhabitants, "outof-place" wild boar are seen as transgressing multiple boundaries and causing "damage" to crops; biologically threatening domesticated livestock; endangering local ecosystems and vulnerable species (Massei et al., 2011;Barrios-Garcia and Ballari, 2012;Ballari and Barrios-García, 2014;Snow et al., 2017); and disrupting everyday human activities in rural areas, edgelands, suburbs and even urban centers (Licoppe et al., 2013;Stillfried et al., 2017). In other words, their increasingly conspicuous presence is often perceived as untenable within contemporary ecologies and economies (Schofield, 2010;Day, 2015;Warner, 2019). ...
Chapter
Full-text available
) Understanding Human–Canid Conflict and Coexistence: Socioeconomic Correlates Underlying Local Attitude and Support Toward the Endangered Dhole (Cuon alpinus) in Bhutan.
Article
Full-text available
The expanding population of wild pig (Sus scrofa) and the associated economic loss has been a challenge for the government and conservation biologists, for over a decade globally. Unlike the majority of other wildlife, rising anthropogenic pressure offered wild pigs a suitable environment to expand their population. Accordingly, the circumstances for social conflict also increased at human–wildlife interface areas. Understanding the regional ecological landscape factors driving the human–wild pig conflict (HWPC) is vital for developing efficient strategies for HWPC management. We analyzed the important spatial and ecological factors determining HWPC across the Eastern and Western Ghats region of Tamil Nadu, India through semi-structured interviews of local communities. Fifty seven percent (n = 825) of the villagers surveyed (n = 1460) reported frequent wild pig conflict, principally in the form of crop damage (n = 819), especially in areas adjoining the forest boundary. Our study indicated that the probability of HWPC was positively correlated to the diversity of major and minor crops grown, percent crop cover and distance to the nearest water body, and negatively correlated to the degree of slope of the landscape and average annual rainfall. We identified 6729 km² of the total sampled area (22,525 km²) of high HWPC. Our HWPC hotspot map provides a concise view of the conflict pattern across the larger landscapes that can help the authorities prioritize areas and concentrate the conflict mitigation measures towards areas that require immediate attention.
Article
Full-text available
The recent and ever-growing problem of boar (Sus scrofa forms including wild boar, hybrid and feral pig) expansion is a very complex issue in wildlife management. The damages caused to biodiversity and the economies are addressed in different ways by the various countries, but research is needed to shed light on the causal factors of this emergency before defining a useful collaborative management policy. In this review, we screened more than 280 references published between 1975-2022, identifying and dealing with five hot factors (climate change, human induced habitat modifications, predator regulation on the prey, hybridization with domestic forms, and transfaunation) that could account for the boar expansion and its niche invasion. We also discuss some issues arising from this boar emergency, such as epizootic and zoonotic diseases or the depression of biodiversity. Finally, we provide new insights for the research and the development of management policies.
Article
Full-text available
Wild pigs, Sus scrofa, an introduced species in California, are hypothesized to compete with native species for food and to consume some native vertebrates. To assess the potential for these impacts, we collected stomach contents of wild pigs over a 1-year period to evaluate seasonal and sex-related variation in diets of wild pigs in oak woodland habitats of the central coast region of California. Diets of the sexes were similar, but diets of wild pigs varied seasonally and related to acorn mast availability during the autumn. The proportion of animal tissue in diets increased concurrently with acorns, supporting earlier studies. Acorn consumption by wild pigs may impact oak regeneration as well as native vertebrates that consume acorns.
Article
The results of an investigation of 155 stomachs of wild boar conducted 1986/87 are presented. The samples were taken from the hunting reserve Belje in "Jelen" (Tab. 1). 100 g of the contents from each stomach were analyzed so that the observed weights could also be used as percentages. The results are presented as average values for the seasons spring, summer, fall, and winter. Shown in Tab. 3 are those for vegetative matter eaten, and those for animal and indefinable matter are in Tab. 4. Table 5 includes the numbers of wild boar for which, distinguished according to season, the uptake of vegetative matter could be demonstrated. Table 6 shows the same for animal matter. The vegetative portion of the stomach contents equalled 94.8%, the animal portion 4.2%, and the indefinable part a negligible 1.0%.
Article
We determined the diet of feral hogs (Sus scrofa; n = 197) in the semi-arid western zone of the South Texas Plains (STP) from stomachs of animals collected from autumn 1989 to autumn 1991 (n = 9 seasons). Vegetation made up approximately 93% of the annual diet by volume. Relative food composition and frequency of occurrence within the diet varied (P < 0.05) on a year and season basis. Diet overlap with large native herbivores was moderate and competition of hogs with these species may be restricted to times of resource scarcity. Animal matter constituted a small (6.7% annually) and seasonally variable part of the diet. A review of threatened and endangered plants and animals within the STP suggested minimal negative impact by direct consumption by feral hogs, though local and nonconsumptive effects could be subtantial.
Article
We investigated the human-wild pig conflict in 5 different states in India. In these states, the wild pig populations are fragmented and relatively isolated all over. Agricultural crop depredation and attacks on humans being by wild pigs is a major problem. During 1990-2008, a total 309 human killing and injury cases were caused by wild pigs in these states. There was marked monthly variation in human casualties. Highest number of casualties occurred in November (n = 61). Wild pigs caused maximum human casualties in forests (73.8%) than crop fields (21.7%) and villages (4.5%). Highest number of 92 human casualties occurred in the age group of 41-50 years. Highest number of 97 human casualties occurred between 0801-1200 h (n = 97). Damage to agricultural crops by wild pigs was of varying extent (5-36%). As a result, people have developed antagonistic attitude towards the wild pigs which adversely affect the conservation efforts. Recommendations have been made for reducing the human-wild pig conflict in these states.