Overview

Brief Summary

Biology

Very little is known about the natural ecology of the Visayan warty pig and few behavioural studies have occurred in the wild (4). These pigs are usually found in groups of 4 to 5 individuals although larger groups and solitary males have also been observed (2). Piglets are born in the dry season that runs from January to March; sows produce an unusually small litter of 1 - 3 piglets (3)(4), and these young have a particularly slow growth rate (4).    Visayan warty pigs feed on a wide variety of forest fruits, roots and tubers, but will also emerge from the forest to plunder cultivated vegetable and cereal crops (6).
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Description

The Visayan warty pig is a little-known, small, forest-dwelling pig that has only recently been recognised as a separate species (2). The males (boars) are much larger than females (sows) (3) and, uniquely amongst wild pigs, develop crests and manes that are up to 23 cm long during the breeding season (4). Sows have only 3 pairs of nipples, a feature that was previously thought to be unique to the pygmy hog (Sus salvanius) (4).
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Distribution

Range Description

This species is endemic to the West Visayan Islands (or Negros-Panay Faunal Region) of the central Philippines, where it previously occurred on Panay, Guimaras, Negros, Cebu, Masbate and (probably) Ticao Islands (Heaney et al. 1998; Grubb 2005; Oliver 1993a; Oliver et al. 1996). It is not known whether S. cebifrons or S. philippensis occurred formerly on the neighbouring island of Siquijor, where wild pigs have also been extirpated, but this species is replaced by S. philippensis on Bohol and all other larger Philippine Islands east of Huxley's Line, except on Mindoro where it is replaced by S. oliveri (Groves 1997, 2001; Oliver 1995, 2001; Oliver et al. 1993). This species has been extirpated from most of its range, and fragmented populations survive today only on Negros, Panay, and possibly Masbate.
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Range

Historically found throughout the Visayan Islands (the central archipelago of the Philippines), this species is now extinct over at least 98% of its former range, with the few surviving populations confined to fragments of remaining habitat on the islands of Negros and Panay (4). Two subspecies are currently recognised; Sus cebifrons cebifrons from the island of Cebu, which was exterminated in the mid-1990s, and S. c. negrinus from Negros. Neither the Panay animals, nor others from Masbate (assuming this population still survives), have been formally described and may represent additional subspecies (4).
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Ecology

Habitat

Habitat and Ecology

Habitat and Ecology
Originally this species occurred in primary and secondary forest from sea-level to mossy forest at 1,600 m asl. Now it occurs mostly above 800 m asl, as there are relatively few patches of suitable habitat in the lowlands (Heaney et al. 1998). It can persist in some degraded habitats such as cogon grasslands as long as there are areas of dense cover, though there is some evidence to suggest that pigs surviving in largely denuded areas are predominately composed of feral animals of mixed origin (W. Oliver pers. comm.).

Systems
  • Terrestrial
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Found in patches of remaining rainforest (2).
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Conservation

Conservation Status

IUCN Red List Assessment


Red List Category
CR
Critically Endangered

Red List Criteria
A4cde

Version
3.1

Year Assessed
2008

Assessor/s
Oliver, W.

Reviewer/s
Leus, K. & Oliver, W. ( Pig, Peccary & Hippo Red List Authority)

Contributor/s

Justification
Listed as Critically Endangered because it is currently undergoing a drastic population decline, estimated to be more than 80% over a period of three generations (estimated to be about 21 years), inferred from the apparent disappearance of several populations, and the effects of over-hunting, habitat loss and hybridization.

History
  • 1996
    Critically Endangered
  • 1994
    Endangered
    (Groombridge 1994)
  • 1990
    Vulnerable
    (IUCN 1990)
  • 1988
    Vulnerable
    (IUCN Conservation Monitoring Centre 1988)
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Status

Classified as Critically Endangered (CR - A1cde, B1+2acd, E) on the IUCN Red List 2002 (1).
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Population

Population
S. cebifrons has been eliminated from three of the six islands where it was known or presumed to have occurred formerly; i.e. Cebu (where the species was last reported in 1960s), Guimaras and Ticao Islands. It is also close to extinction, if not already "functionally extinct", on Masbate, where the species was last confirmed in 1993, at which time only a few individuals were reported to survive in one location. Consequently, potentially viable populations now survive only in the last remaining forest fragments on Negros and Panay Islands (collectively comprising c. 6% and >4% of land area, respectively). though genetic contamination via hybridization with free-ranging domestic or feral pigs has also been confirmed as occurring in most (perhaps all) of these populations (Oliver, 1993a, 1995, 2001).

Population Trend
Decreasing
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Threats

Major Threats
All of the few remaining populations of these animals are now widely fragmented and declining; both through former widespread commercial logging operations, continued low-level illegal logging and agricultural expansion (particularly slash-and-burn cultivation or "kaingin") and hunting pressure. The latter continues throughout its remaining range, both by local farmers in hinterland communities and recreational hunters from larger cities. Both of these groups may also sell any surplus meat which usually commands at least twice the price of domestic pork in local markets and speciality restaurants. Efforts to reduce or discourage hunting are unfortunately also often compromised by generally negative attitudes towards these animals, which can cause severe damage to crops planted within or close to existing forest boundaries, and which are therefore regarded as pests and, hence, a legitimate target for hunting activities (Oliver et al. 1993). Unfortunately, this species is also threatened by genetic contamination via hybridization with free-ranging domestic and feral animals of ex-S. scrofa origin, and hybrids have been confirmed from almost all remaining population sites (Blouch, 1995; Oliver, 1995; 2001).
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The Visayan warty pig is highly endangered; the species has been lost from 3 of the 6 major islands where it was found, and is on the verge of disappearing from a fourth (4). Deforestation in the Philippines has been widespread and habitat loss along with hunting pressure is one of the main causes of the precipitous decline in numbers. Interbreeding with domestic pigs provides a further threat to the few surviving populations and it seems unlikely that purebred forms will persist in the wild for long (4). These pigs also suffer from persecution by local farmers who view the animals as pests; they are subject to high levels of illegal hunting pressure for local consumption, are caught in pitfall traps or wire snares, and may sometimes be killed with explosive devices that are baited and buried in the ground, to be excavated by rooting individuals (6).
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Management

Conservation Actions

Conservation Actions
S. cebifrons is now fully protected by Philippine law, though enforcement of protection measures is generally poor in most areas, including many 'protected areas', owing to lack of resources and other factors. The species occurs in small populations in several 'natural parks', including Mount Canlaon (8,000 ha); North Negros (c. 18,000 ha); Mount Talinis/Lake Balinsasayao (c. 11,000 ha); and the proposed West Panay Mountains Natural Park (c. 70,000 ha). However, the formal declaration of the latter area was eventually stymied by lack of unanimity amongst relevant LGUs and a number of separate, smaller areas have since been declared, though these do not cover all of the most important sites, nor have any of these areas been significantly better protected since declaration owing the absence of any corresponding national budgetary allocations.

The Visayan Warty Pig Conservation Programme (VWPCP) was formally established in 1992 under the aupices of a new Memorandum of Agreement (MOA) between the Department of Environment and Natural Resources (DENR, Government of the Philippines) and the Zoological Society of San Diego (ZSSD, USA), to facilitate development and implementation of a wide-range of conservation-related activities. These include wide-ranging surveys and other field research, education awareness campaigns, assistance in the establishment of new protected areas, diverse personnel training and other local capacity-building initiatives. The latter also including assistance in the establishment of three local threatened species rescue and breeding centres (one on Panay and two on Negros) with a view to the establishment of properly structured conservation breeding programmes and, hence, the accession and management of pure-bred founder populations of these animals whilst the opportunity to do still existed. The ensuing breeding programme has since been extended to other breeding centres locally and internationally, and is hoped that this will also enable future reintroductions of these animals to selected sites in Cebu and other islands (Oliver 1993a,b, 2004; Oliver and Wirth, 1997; Lorica and Oliver, 2007).

Recommended conservation actions include:

1. Enhance management and protection of existing protected areas and/or assist establishment of new 'local conservation areas' (in effect 'municipal reserves') and/or private nature reserves

2. Reinvestigate the current status of this species on Masbate and develop and implement relevant conservation management recommendations for the enhanced future protection of any remaining native forest habitats and the potential future reintroduction of this (and other West Visayan endemic species) on this island and on Cebu

3. Implement priority recommendations re. local awareness raising arising from recent, range-wide 'ethnobiological' surveys, revealing both currently low levels of awareness re. local protection legislation and prevalence of 'recreational', 'reprisal' or 'commercial' (rather than 'subsistence') hunting in all key sectors.

4. Conduct (or complete) systematic (including mtDNA) research on intra- and inter-population variation amongst surviving Negros and Panay Island populations.
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Conservation

The Visayan Warty Pig Conservation Programme was established in 1991 (4), with the long-term aim of reintroducing 'warties' into areas from which they have been lost (3). Two captive breeding and rescue centres have been established on Negros, one by Silliman University and another at the Negros Forests and Ecological Foundation (4). In addition, a centre has been established on the island of Panay by the College of Agriculture and Forestry; as of June 2001, the total captive population for the species was 41 (4). The Visayan Warty Pig Conservation Programme is also involved with research into these poorly understood pigs and works to increase local awareness of the issues involved. The Philippines has more species of wild pig than any other nation, however, most of these are severely endangered, and habitat loss and hunting are rife; the efforts to save the Visayan warty pig are a battle against time (3).
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Wikipedia

Visayan warty pig

The Visayan warty pig (Sus cebifrons) is a critically endangered species of pig. The Visayan warty pig is endemic to two of the Visayan Islands in the central Philippines, and is threatened by habitat loss, food shortages, and hunting – these are the leading causes of the Visayan warty pig's status as critically endangered. Due to the small numbers of remaining Visayan warty pigs in the wild, little is known of their behaviors or characteristics outside of captivity.

Subspecies[edit]

  • Negros warty pig (Sus cebifrons negrinus). There are two separate remaining populations of S. c. negrinus – on the islands of Negros and Panay, respectively. Both populations have been physically and genetically isolated since the last ice age (c. 12,000 yrs). The current conservation program for S. c. negrinus includes successful breeding programs at the Rotterdam Zoo for pigs of Negros origin, and at the San Diego Zoo for pigs of Panay origin.

Although it is believed that S. cebifrons can now only be found in Negros and Panay, some studies report of the possibility that a small population exists on the island of Masbate.

Distribution[edit]

The Visayan warty pig is endemic to six islands in the Philippines. It is now extinct on four of the islands. It is endangered because Filipino natives captured them and use them for resources, such as food and using its skin for fur.

Physical characteristics[edit]

The Visayan warty pig receives its name from the three pairs of fleshy "warts" present on the visage of the boar. Biologists speculate that the reason for the warts is to assist as a natural defense against the tusks of rival pigs during a fight. The boars also grow stiff spiky hair.

Habitat and diet[edit]

Visayan warty pigs tend to live in groups of four to six. The diet of the pig mainly consists of roots, tubers, and fruits that can be found in the forest. They may also eat cultivated crops. Since approximately 95% of their natural habitat has been cleared by local farmers who cut down the forest to plant crops, the propensity of the pigs to eat cultivated crops has risen dramatically. Because the land that is cleared for farming is often unproductive after a few years, the food sources of the Visayan warty pig are extremely limited, a factor that has contributed significantly to the pig’s dwindling numbers.

Reproduction[edit]

Visayan Warty Pig piglets, Sus cebifrons

Visayan warty pig piglets are often seen during the dry season between the months of January and March in their native habitat of the western Visayan Islands. The mean number of piglets is three to four per litter.

Captive status[edit]

In addition to a few other conservation programs in the Philippines, the Crocolandia Foundation and the Negros Forests and Ecological Foundation, Inc., both have this species in captivity. In Europe, nine zoos – the Rotterdam Zoo, Poznan Zoo, Chester Zoo, Belfast Zoo, Edinburgh Zoo, Blackbrook Zoological Park, Děčín Zoo, the Newquay Zoo, and the Parken Zoo in Eskilstuna – maintain the Negros Island variety of this species. Moreover, several zoos in the United States also maintain this species. The San Diego Zoo was the first zoo outside the Philippines to keep and breed Visayan warty pigs. Elsewhere in North America, zoos in Seattle, Los Angeles, Portland, Phoenix, Tucson, Miami, Tampa, Saint Louis, Brevard Zoo, and Boise have also kept the species.

See also[edit]

References and external links[edit]

  1. ^ Oliver, W. (2008). Sus cebifrons. In: IUCN 2008. IUCN Red List of Threatened Species. Retrieved 5 April 2009. Database entry includes a brief justification of why this species is of critically endangered.
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