 Sus
cebifrons
Visayan warty pig |
Taxonomy | Description
| Reproduction | Ecology
| Behavior | Distribution
| Conservation | Remarks
| Literature |
Taxonomy
Classification
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Kingdom :
Phylum :
Class :
Order :
Suborder :
Family :
Tribe :
Genus : |
Animalia
Chordata
Mammalia
Cetartiodactyla
Suiformes
Suidae
Suini
Sus |
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Sus cebifrons [Heude, 1888].
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Citation: Mem. Hist. Nat. Emp. Chin., 2, pl. 17, fig. 5.
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Type locality: Philippines, Cebu Island.
The taxonomic record (above) is taken from Wilson and Reeder (1993). Wild
pig taxonomy has changed significantly in recent years: only in 1993 did
Sus cebifrons become widely recognized as a separate species.
Prior to this, the Visayan warty pig was considered by various authors
to be a subspecies of either the Sulawesi warty pig (i.e. Sus celebensis
negrinus) or the bearded pig (Sus barbatus cebifrons;
see Groves, 1997). Given its history of being included within
other pig species, it is perhaps surprising that recent molecular research
indicates that this species is possibly the most genetically distinct member
of genus Sus (Oliver, 2004b)
Some authors consider the Visayan warty pig to be monotypic (Groves and Grubb,
1993), while other recognize two subspecies based on islands of origin: S.
c. cebifrons, now extinct from Cebu, and S. c. negrinus from
Negros (Groves, 1997). A third subspecies from Panay may exist,
but the required studies on body and skull morphology have not yet been conducted
(Oliver, 2004a). S. negrinus is a synonym for S. cebifrons
(Wilson and Reeder, 1993).
General Characteristics
Like many island species, the Visayan warty pig is relatively small in size
(Oliver et al., 1993). Males are much larger than females, with
up to a four-fold difference in body weights between the sexes (Rabor, 1977;
Lastica, 2003). These pigs are usually lean, but can become obese in
captivity (Lastica, 2006).
Reported measurements for Visayan warty pig (Sus cebifrons) |
| Source |
Adult Weight |
Head & Body Length |
Shoulder Height
|
Tail Length |
| Lastica, 2003 |
35-40 kg 
20-35 kg  |
- |
- |
- |
Lastica, 2006
Estimates from Negros |
up to 80 kg
20-35 kg |
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up to 50-55 cm
30-45 cm |
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Rabor, 1977
for S. c. negrinus |
- |
114 cm
95.7 cm |
63 cm
45.6 cm |
23 cm |
S. cebifrons is dark grey or black in overall color (Groves, 1997;
Lastica, 2003). Sparse bristly hairs cover most of the body - in females
and young males these are predominantly black in color, while in adult males
there is often a predominance of silver- of fawn-colored bristles (Rabor,
1977; Groves, 1997; Lastica, 2003). Skins of adult males from Negros
have an especial predominance of white hair on the shoulders and sides (Groves
and Grubb, 1993). A tuft of hair is usually present on the crown of
the head; this tends to be either dark reddish-brown or black with scattered
red or straw-colored hairs (Groves, 1997). In males (and females to a
lesser extent) from Panay, this tuft is expanded into a long mane which extends
from the forehead down the back to the rump (Groves and Grubb, 1993). This
mane is grown and shed annually, and is one of the most distinctive characters
of this species, often flopping over the face of the boar, obscuring the
eyes.
The body is typical of pigs, being barrel-like in form with relatively short
legs. Females possess three pairs of mammary glands (also present,
but not functional, in males). Other native and domestic Filipino pigs
- as well as hybrids between these species and S. cebifrons - possess
at least four pairs, providing an important key in the identification
of purebred Visayan warty pigs (Lastica, 2003).
The high-crowned skull is relatively small in both sexes, and sexual dimorphism
is highly evident in skull morphology (Groves, 1997). Groves and Grubb
(1993) provide a few cranial measurements. Externally, the head is
elongated with a terminal nasal disc. The ears are small and upright,
with slightly pointed tips (Lastica, 2003). Despite being named
a "warty pig", the facial warts of S. cebifrons are typically small;
males from Panay have the largest warts (Groves and Grubb, 1993; Groves,
1997). Visayan warty pigs never grow gonial warts (on the angle of
the jaw) - this spot is marked in males by a wide white tuft of hair; in
females, there is usually no tuft and only a small white spot present (Groves
and Grubb, 1993; Groves, 1997). Male Visayan warty pigs possess large
canines which protrude from the mouth as tusks (Lastica, 2003).
In both sexes, the face is marked with a conspicuous whitish stripe which
crosses the bridge of the nose just behind the mouth and follows the
jawline to the angle of the jaw (Groves, 1997; Lastica, 2003). This
band is generally less obvious in females than males, but is one of
the primary distinguishing characteristics for distinguishing S.
cebifrons from other Philippine wild pigs (Lastica, 2003).
Ontogeny and Reproduction
The gestation period for S. cebifrons is approximately 118 days (Oliver,
1996 in Lastica, 2003). One to two weeks prior to giving birth,
females begin showing nesting behavior and may become aggressive to conspecifics
(Oliver et al., 1993). Females usually give birth overnight,
and are very protective of their offspring (Lastica, 2003). Reports
from native hunters indicate that the average number of piglets per litter
in the wild is three or four (Oliver et al., 1993), while Lastica
(2003) suggests average litter size is two or three. These figures
are corroborated by captive births: six of ten North American captive-born
litters contained three offspring, with half of the remaining four litters
contained two and four offspring each (ISIS, 2005). A record number
of five offspring in a litter was observed in two Philippine breeding centers
in 2005, although the piglets had to be weaned earlier than usual to help
the female regain condition (Lastica, 2007). In the wild, piglets are
usually observed from January to March, during the region's dry season (Oliver
et al., 1993).
Young Visayan warty pigs are marked with thick stripes which run from the
shoulders to the rump, alternating between orange-brown and black (Groves,
1997; Lastica, 2003). There are typically four black stripes; one pair
runs down the back on either side of a lighter dorsal line, with another
stripe running on either side along the flanks and haunches (Groves, 1997).
The striping of the juvenile coat loses definition at seven to nine
months of age, and adult coloration is fully achieved after one year (Rabor,
1977; Lastica, 2003). Youngsters begin testing solid food at one week
of age, and may be weaned by six months (Lastica, 2003). Females are
capable of producing a litter every 8 to 12 months (ISIS, 2005).
Females reach sexual maturity at two or three years of age; males may be
sexually mature at two years, but do not possess the fully-developed
characteristics of adult males (Lastica, 2003). In the wild, Visayan
warty pigs are believed to live up to 10-15 years (Lastica, 2003).
Ecology and Behavior
Knowledge of the Visayan warty pig from the wild is very scarce, due to the
rarity of this species, the scarcity of natural habitat, and the difficulties
of observing these animals in the wild. This species was once found
in a wide variety of habitats, ranging from lowland and highland
grasslands as well as primary and secondary forest (Rabor, 1977). This
species is now restricted to densely forested areas on just two islands in
the Philippines (Rabor, 1977).
This species is sociable, living in groups of three to over a dozen animals.
The composition of these groups is typically a single adult male with
several females (usually three or four, as indicated by local hunters) and
young individuals of both sexes (Rabor, 1977; Oliver et al.,
1993). Solitary males have also been reported, but are encountered
only rarely (Oliver et al., 1993).
In captivity, S. cebifrons will use mud wallows (Lastica, 2003).
While pigs are generally not excellent jumpers, one juvenile female
on Negros was observed clearing a meter-high fence during a capture attempt
(Lastica, 2003).
S. cebifrons, like most pig species, is omnivorous (Lastica, 2003).
As determined though indirect observations of tracks and scat, Visayan
warty pigs appear to feed on plant species such as Lithocarpus (Fagaceae),
Platea excelsa (Icainaceae), and Dillenia reifferscheidia
(Dilleniaceae) (Hamann and Curio, 1999). These authors suggest that
Lithocarpus and Dillenia may depend solely on S. cebifrons
for seed dispersal. Other plant species identified in the diet by Cummings
(2003, in Lastica, 2003) include "Gabe gabe" and "Silan" (Colocasia
sp. - a favorite of this species), "Lintakuban" (a fruiting tree), "Kagay"
vine, "Tugis" palms, wild bananas, avocado, "Batwan", "Lumboy lumboy", and
casava. Earthworms ("Duduloy") are frequently consumed (Cummings, 2003,
in Lastica, 2003).
Distribution
S. cebifrons is endemic to the Negros faunal region of the Philippines,
encompassing the Visayan Islands of Cebu (where it is now extinct), Negros,
Panay, and Guimaras (now extinct) (Groves and Grubb, 1993). This
species may also be present on the island of Masbate, and may once have lived
on Siquijor and Bohol (where it is now believed to be extinct) (Oliver,
1995).
Countries: Philippines (IUCN, 2004).
Range Map (Redrawn from Oliver, 1995)
Conservation Status
The Visayan warty pig has been listed as critically endangered (Criteria
A1cde, B1+2acd, E) by the IUCN (2006), but is not listed by CITES. It
is one of the most endangered species of wild pig, being extinct in
over 95% of its former range and now found only in small, fragmented populations
(Oliver, 2004a; Oliver, 2004b). There have been no recent published
estimates of population numbers surviving in the wild.
While small isolated populations face numerous problems sustaining
their numbers, in the case of the Visayan warty pig there are far more
pressing concerns. Human impacts - including habitat destruction,
persecution (a result of crop raiding), and intensive hunting for meat -
continue to reduce both absolute numbers of Visayan warty pigs and their
potential to maintain (nevermind expand) their numbers by reducing available
resources (Oliver, 2004b; IUCN 2006). Domestic pigs pose a significant
threat to this species, hybridizing with wild warty pigs as well as
introducing diseases and parasites. Visayan warty pigs killed by poachers
now show (with increasing frequency) obvious hybrid characters, including
large ears, reduced manes, and even piebald markings (Oliver, 2004a).
Three rescue and breeding centers for this species have been created
within the Philippines, and an international breeding program is underway,
with captive stock in both North America and Europe (Oliver, 2004a; Oliver
2004b).
Remarks
Sus is Latin, meaning a pig. The species name
cebifrons is likely a combination of Cebu (the island on which the
type specimen was collected), and the Latin word frons, meaning the
forehead or brow, a reference to the long mane and forehead tuft.
Although now extinct on the island of Cebu, S. cebifrons is
sometimes called the Cebu bearded pig as a result of the provenance of the
type specimen.
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Local names
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Baboy ilahas (on Visayas; literally "wild pig") from Rabor,
1977; Lastica, 2003; Lastica, 2007
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Baboy do mor [Local Philippine dialect] from Oliver, 2004a
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Baboy talunon (on Negros) from Lastica, 2003
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Manggalisak banban (half-grown male in Bisayan) from Rabor, 1977
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Biggal (sow in Bisayan) from Rabor, 1977
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Bakatin (small pig in Bisayan) from Rabor, 1977
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Literature
Cited
Groves, C. P. 1997. Taxonomy of wild pigs (Sus) of the
Philippines. Zoological Journal of the Linnean Society; 120(2): 163-191
Groves, C. P., and P. Grubb. 1993. The Eurasian suids, Sus
and Babyrousa - Taxonomy and Description. In Pigs, Peccaries
and Hippos: Status Survey and Action Plan. Edited by W. L. R.
Oliver. Gland, Switzerland: IUCN. pp. 129-136.
Available online.
Hamann, A. and E. Curio. 1999. Interactions among frugivores
and fleshy fruit trees in a Philippine submontane rainforest. Conservation
Biology; 13(4): 766-773.
ISIS (International Species Information System). 2005 Specimen
Records.
IUCN (International Union for Conservation of Nature and Natural Resources).
2006. 2006 IUCN Red List of Threatened Species.
Available online.
Lastica, E. A. 2003. Visayan Warty Pig (Sus cebifrons)
- Species husbandry guidelines. Philippines Biodiversity Conservation
Programmes.
Lastica, E. A. 2006. Personal Communication (February 2006).
Programme Assistant, Philippines Biodiversity Conservation
Programmes; Consultant Curator, Silliman University - Center for Tropical
Conservation Studies
Lastica, E. A. 2007. Personal Communication (June 2007).
Coordinator of the Threatened Species Conservation Breeding Programmes,
Philippines Biodiversity Conservation Programme; Consultant Curator, Silliman
University - Center for Tropical Conservation Studies
Oliver, W. L. R., C. R. Cox, and C. P. Groves. 1993. The Philippine
Warty Pigs (Sus philippensis and S. cebifrons).
In Pigs, Peccaries and Hippos: Status Survey and Action Plan.
Edited by W. L. R. Oliver. Gland, Switzerland: IUCN.
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Oliver, W. L. R. 1995. The taxonomy, distribution and status of Philippine
wild pigs. IBEX (Journal of Mountain Ecology); 3: 26-32.
Oliver, W. L. R. 2004a. First (and last?) breeding loan export of Visayan
(Negros) warty pigs. Suiform Soundings (PPHSG Newsletter); 4(1): 25-27.
Oliver, W. [Compiler]. 2004b. Summary of group activities during
the past quadrennium. Suiform Soundings (PPHSG Newsletter); 4(2): 43-45.
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the Philippines Press, Quezon City, Philippines.
Wilson, D. E., and D. M. Reeder [editors]. 1993. Mammal Species of the World
(Second Edition). Washington: Smithsonian Institution Press.
Available online.
Additional Resources
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threatened suids of South and Southeast Asia. Journal of Mountain Ecology;
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Philippines (Part 2). In Wild Plants as Potential Feeds for
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College, Laguna, Philippines. pp. 17-29.
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the depredations of wild pigs in the Philippines. (Unpubl.) Ph.D. thesis,
Oklahoma State University, Stillwater, Oklahoma: 237 pp.
Cox, C. R. 1985. A field survey of the distribution and conservation
status of the wild pig (Sus barbatus cebifrons) and Prince Alfred's
spotted rusa (Cervus alfredi) in the Visayan Islands, Republic of
the Philippines. (Unpubl.) report to the IUCN/SSC Pigs and Peccaries Specialist
Group: 27 pp.
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Cox, C. R. 1987. A preliminary survey of the proposed Panay Mountains
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Cummings, M. J. 2003. An Assessment of the Visayan Warty Pig,
Sus cebifrons in the Imbang-Caliban Watershed, North Negros Forest
Reserve, Philippines: Ecological and Social Perspectives. MSc Conservation
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Forest Management Bureau. 1988. Natural Forest Resources of the
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Groves, C. P. 1981. Ancestors for the Pigs: Taxonomy and Phylogeny
of the Genus Sus. Tech. Bull. No. 3, Dept. of Prehistory, Research
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*Lucchini, V., E. Meijaard, C. H. Diong, C. P. Groves, and E. Randi. 2005.
New phylogenetic perspectives among species of South-east Asian wild
pig (Sus sp.) based on mtDNA sequences and morphometric data.
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MacKinnon, J., and K. MacKinnon. 1986. Review of the Protected
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*Mudar, K. M. 1986. A morphometric analysis of the five subspecies
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