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Chapter 22: Pygmy hog Porcula salvania (Hodgson, 1847)Taxonomy
The species was originally named Porcula salvania by Hodgson
(1847). This was amended by Garson (1883) to Sus salvanius as
he, and several other authors, including Corbet and Hill (1980)
and Groves (1981), later concluded that various dental and other
characters described by Hodgson were based on the immaturity
of the type specimen and were insufficient to merit generic dis-
tinction from other members of the genus Sus. However, a phy-
logenetic study using pygmy hog’s mitochondrial DNA (Funk
et al. 2007) confirmed its original classification and the name
Porcula salvania was restored and has since been universally
accepted.
Subspecies and Distribution
The pygmy hog belongs to monotypic genus Porcula and there
are no subspecies described for the species P. salvania.
Past distribution: The species was formerly distributed along
the narrow alluvial tract south of Himalayan foothills from
south-eastern Uttarakhand in the west to central Assam in the
east, along the international border of Nepal and Bhutan with
Indian states of Uttar Pradesh (UP), Bihar, West Bengal, and
Assam (Oliver 1980; Oliver & Deb Roy 1993). The landscape,
known as terai in UP and Nepal and as duar in north Bengal and
western Assam, consists of more or less flat and relatively well-
drained terrain covered with riverine forests and tall grasslands
in the flood plains of the tributaries of the rivers Ganges and
Brahmaputra. The pygmy hogs occupied some of the grassland
patches in this tract.
The information on its distribution prior to 1970s is scanty
and imprecise and the species was never reported to be plenti-
ful. By the 1960s, it was already feared extinct by Gee (1964) and
others. Much more information became available after the spe-
cies was ‘rediscovered’ in 1971 near Barnadi Wildlife Sanctuary
and in Manas National Park (Mallinson 1971; Tessier-Yandell
1971), both located along Assam’s border with Bhutan. Surveys
in 1977 by Oliver (1979, 1980) confirmed the species’ continued
presence in Manas, Barnadi and some other reserve forests in
Assam, e.g. Subankhata, Daranga, Rowta, Balipara, Nauduar,
and Gohpur, but not in Khalingduar from where it was reported
earlier (Ranjitsinh 1972) or other grassland areas. Despite rec-
ommendations for improved management and protection of
grassland habitats by Oliver (1979, 1980), particularly against
extensive dry-season burning, organized thatch collection,
commercial plantation of trees, livestock grazing, and other
human uses, little was done and most of the populations disap-
peared by the early or mid 1980s. By 1985, wild populations only
survived in and around Manas and in Barnadi (Oliver & Deb
Roy 1993).
Several attempts to locate pygmy hog in Nepal between 1964
and 1984 (Griffith 1978; Rands et al. 1979; Oliver 1984) and sur-
veys in suitable habitats in Uttarakhand, Uttar Pradesh, Bihar,
West Bengal, and Bangladesh (Oliver 1984) failed to verify its
continued existence in these states and countries. Anecdotal
accounts of its occurrence in some areas south of the river
Brahmaputra in Cachar and Goalpara districts of Assam were
also investigated, but no trace of these animals was found during
brief surveys in the late 1970s and early 1980s (Oliver 1979,
1980; Oliver & Deb Roy 1993) or in the mid 1990s (Narayan &
Oliver 2015).
Present distribution (see Figure 22.1): Extensive surveys were
again carried out between 1995 and 2000 (Narayan & Oliver
2015) in all areas of north-eastern India where pygmy hogs had
been reported or suspected to occur in the past. These surveys
included grasslands along Assam’s border with Bhutan and
Arunachal Pradesh, parts of Cachar, Hailakandi and Karimganj
districts of southern Assam, the Goalpara district of western
Assam, the West Garo Hills district of Meghalaya, the Mon
district of Nagaland, and some other areas. Certain large tracts
of plains grasslands in Arunachal Pradesh, in extreme south-
east Siang and Dibang Valley districts (e.g. D’Ering Memorial
Wildlife Sanctuary, Siku and Dibang Reserve Forests) and in
west Lohit district (Paya and Digaru grasslands) were also inves-
tigated, but no evidence was found of this species in any of the
above areas, despite the presence of superficially suitable habi-
tats in some places.
These surveys confirmed the extinction of the species in
Barnadi, where the species was last recorded definitively in
1991, and all other sites except Manas National Park, which now
supports the last known viable wild population of this species.
Tiny remnant populations may persist in other reserve forests
of Manas Tiger Reserve, but all of these areas are disturbed and
poorly protected, and it is most unlikely that these populations
remain viable or can be salvaged. Bhutan has little low-altitude
grassland plains other than a few small pockets in Royal Manas
National Park where a few pygmy hogs may survive mostly in
areas contiguous with those in Indian Manas. However, there
are no confirmed records of the species from Bhutan in the
recent past.
Political unrest and insurgency during ethnic disturbances
in Assam in the late 1980s and the 1990s was responsible for
the deterioration of the security situation in and around Manas.
Although the situation has gradually improved and the Park is
slowly recovering, the pygmy hog habitat in the alluvial grass-
land belt along the southern boundary of the Park remains dis-
turbed due to its proximity to the exploding human population
and the resource needs of economically backward communities.
The estimated original population of the species in Manas
National Park has gone down from 400–500 to about 200–250
in the two decades after the mid 1990s due to degradation and
shrinking of suitable habitat (Narayan & Oliver 2015). In the
same period, conservation measures have also contributed to the
partial recovery of the species. A hundred captive-bred pygmy
hogs were reintroduced in restored habitats in three protected
areas of Assam between 2008 and 2016 (see Reintroductions and
Post-release Monitoring Methods below). It has been particularly
successful in the RG Orang National Park, where the popula-
tion has increased to over 100 hogs following the release of 59
animals over a period of five years.Descriptive Notes
The following descriptions are largely based on Groves (1981),
Groves and Grubb (1993), Oliver (1980), and Narayan and
Oliver (2015)..02412:46:11