Porcula salvania, Hodgson, 1847
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publication ID |
https://doi.org/ 10.5281/zenodo.5721014 |
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DOI |
https://doi.org/10.5281/zenodo.5721116 |
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persistent identifier |
https://treatment.plazi.org/id/038087E8-552A-5627-8BBD-035F1944F537 |
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Conny |
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scientific name |
Porcula salvania |
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17. View On
Pygmy Hog
French: Sanglier nain / German: Zwergwildschwein / Spanish: Jabali pigmeo
Taxonomy. Porcula salvania Hodgson, 1847 ,
Sikkim Terai, India.
After having been included in Sus for a long time, the species was reassigned to its original genus Porcula . Monotypic.
Distribution. NE India (NW Assam). View Figure
Descriptive notes. Head-body 55-71 cm, tail 2: 5 cm, shoulder height about 25 cm; weight 6.6-9. 7 kg. Females are a little smaller and the newborn babies weigh only 150-200 g. The greatest skull length is 17-9 cm. Pygmy Hogs differ from members of the genus Sus in the extreme reduction in body, ears, and tail size, relatively short medial false hooves, and snout disc perpendicular to axis of head. There is an absence or warts or whorls on the jaw, and the body shape is more streamlined than that of other pigs. In adults, the profile tapers from relatively longer hindquarters to smaller forequarters. The adult dentition in the Pygmy Hog is similar to Sus .
Habitat. Pygmy Hogs prefer undisturbed grassland typical of early successional riverine communities, comprising dense tall grass mixed with a wide variety of herbs, shrubs, and young trees. Such grasslands, dominated by Narenga porphyrocoma, Saccharum spontaneum, S. bengalensis, Imperata cylindrica, and Themeda villosa, form characteristic associations 2-3 m in height. However, most such early successional communities are subject to wide-scale annual burning and accordingly are characterized by low diversity and the overwhelming preponderance of a few, fire-resistant grasses. Therefore they almost certainly constitute suboptimal habitats for Pygmy Hogs and most other grassland dependent species, which are deprived of cover and other resources for protracted periods prior to the early season rains. The species is not found in structurally similar grasslands located in riverine floodplains, which are subject to prolonged inundations during the monsoon. These grasslands are generally fertile alluvial areas, making them desirable for agriculture. Human use of these habitats contributes to the rapid decline of Pygmy Hogs throughout their known or presumed former range.
Food and Feeding. Pygmy Hogs feed on roots, tubers, shoots, and ground vegetation, along with worms and other invertebrates and, probably, small vertebrates (e.g. reptiles and the eggs and nestlings of ground-nesting birds).
Breeding. Reproduction is strongly seasonal, with almost all births occurring during a single, well-defined birth peak, which coincides with the onset of the monsoon,in late April and May in western Assam. Litter size varies from two to six, but is usually 3-4. The species is unusual among the suids in that nests are constructed and used by both sexes at all times of the year and nest building is not limited to farrowing.
Activity patterns. The species seems to be most active during the day, although this remains poorly studied. A study of diurnal activity patterns in captive animals revealed that the highest proportion of observation time was dedicated to foraging and moving, followed by being inside the nest, resting, displaying, and allogrooming. The two sexes partitioned their time rather differently. Females seemed to spend more time on foraging than males, while males moved more than females, which was associated with elevated levels of display behavior and courtship performed by them. Display was exhibited only by males and performed during the breeding season. Allogrooming was the most prominent social interaction observed, with certain individuals grooming more than others. Moreover, among the breeding pairs, males groomed considerably more than females. It is possible that male Pygmy Hogs move a lot and display considerably to increase their potential reproductive success. Because these observations were on captive animals it is not clear how these time budgets would be changed under natural conditions, where the presence of predators and other factors would likely change their behavior.
Movements, Home range and Social organization. Adult male Pygmy Hogs usually are seen by themselves, but are reported to join estrous sows during the rut and to associate loosely at other times of the year with the basic natal social family units. These units usually consist of 4-6 individuals, including one or more adult females and accompanyingjuveniles.
Status and Conservation. CITES Appendix I. Classified as Critically Endangered on The IUCN Red List, putting the species among the most endangered of all mammals. It is also listed in Schedule I of the Indian Wildlife (Protection) Act, 1972. Historically Pygmy Hogs were known from only a few locations in northern West Bengal and north-western Assam in India. The species is now believed likely to have occurred in an area of tall alluvial grasslands that extended in a narrow belt south of the Himalayan foothills from north-western Uttar Pradesh and southern Nepal to Assam, possibly extending at intervals into contiguous habitats in southern Bhutan. Records are scarce because the species was seldom observed in the wild state, on account of the former inaccessibility ofits habitat, to which these animals are supremely adapted by virtue of their diminutive body size and other characters. After at least two decades without reported sightings the species was feared extinct. However, in 1971 it was coincidentally “rediscovered” in two separate locations in north-western Assam, Barnadi Wildlife Sanctuary in Darrang District and Manas National Park. Subsequent field surveys confirmed its continued occurrence in several other forest reserves in north-western Assam in the late 1970s, but continued commercial forestry operations resulted in its extirpation in all of these areas by the early 1980s and in Barnadi by the late 1980s/ early 1990s, despite the latter area having been upgraded to a wildlife sanctuary to try to protect it. Extensive surveys of grasslands in other parts of its known or presumed former range in other north-eastern Indian states and neighboring parts of southern Nepal and Bhutan during the 1980s and early 1990s also failed to locate any surviving populations. These findings substantiated growing concerns that the species had been reduced to only a few disparate locations in and around Manas National Park, all of which were subject to deliberate dry-season burning and other disturbances. To make matters worse, north-western Assam was also beset by local socio-political turmoils that spilled over into Manas in the early 1990s. Commercial poachers promptly decimated key populations of Greater One-horned Rhinoceros (Rhinoceros unicornis), Barasingha (Rucervus duvaucelii ranjitsinhi), and other species. Fortunately, Pygmy Hogs were either too small or too difficult to catch to be similarly targeted, though the species nonetheless remains severely threatened throughout its last remaining range, even in Manas, because of degradation of its habitat via profligate levels of dry-season burning, risk of disease through increased incursions by domestic livestock and other factors. The main threats to survival of Pygmy Hog are loss and degradation of habitat due to human settlements, agricultural encroachments, flood control schemes, and traditional forestry management practices. Some management practices, such as planting of trees in the grasslands and indiscriminate use offire to create openings and to promote fresh growth of grass, have caused extensive damage to the habitats the authorities intend to protect. In fact, large scale burning of grass in the dry season remains the single most important threat to the continuing survival of these animals, though the reduction and fragmentation of their habitat and other anthropogenic disturbances also bring increased risks of contagious disease via contact with domestic livestock and other factors. A “Conservation Action Plan for the Pygmy Hog,” originally prepared by the ITUCN/SSC Pigs and Peccaries Specialist Group and the Jersey Wildlife Preservation Trust, and submitted and agreed upon in principle by both the Union Ministry of Environment and Forests and the Assam State Government, in 1981, was finally and formally approved in 1995. This agreement enables the implementation of various field studies, follow-up status surveys, education and awareness campaigns, personnel training, and local community assistance projects. A highly successful conservation breeding program was also initiated in 1996, following the construction of the “Pygmy Hog Conservation Research and Breeding Centre” located on the outskirts of the Assam State capital, Guwahati, and the capture of two male and four female Pgymy Hogs in Manas. This capture operation, undertaken in close collaboration with Park officials, was timed to coincide with the expected mid-term pregnancy of the adult sows, to increase the number of genetically represented individuals (i.e. wild sows that had been impregnated by other wild males) and therebytriple the number of captive individuals within six weeks. (Three of the four sows produced a total of thirteen infants, all but one of which survived.) Subsequent breeding soon resulted in over crowding and a need to manage the numbers and identities of individuals producing litters each year. A custom-built “pre-release” facility located at Potosali, close to Nameri National Park in north-west Assam, was built, with several large enclosures with habitats where animals scheduled for reintroduction into selected protected sites learned to forage for themselves. The first releases took place in the Sonai Rupai Wildlife Sanctuary, and the first wild births were recorded the following year. More releases were conducted in 2009 and 2010, and several additionalsites have been identified for similar reintroduction efforts in the coming years.
Bibliography. Bell & Oliver (1992), Deb (1995), Funk et al. (2007), Mallinson (1971, 1977), Narayan (2004), Narayan & Deka (2002), Narayan, Deka, Chakrobarty & Oliver (1999), Narayan, Deka & Oliver (2008a, 2008b), Narayan, Deka, Oliver & Fa (2009), Narayan, Oliver et al. (2008), Oliver (1977, 1978, 1980, 1981, 1989, 1991a, 1991b), Oliver & Deb Roy (1993), Oliver et al. (1997), Sanyal (1995).
No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.
