|
Pigs, Peccaries and
Hippos Status Survey and Action Plan (1993) Chapter 5. 3 The Pigmy Hog (Sus salvanius) William L. R.
Oliver and Sanjoy Deb Roy Status and Action Plan Summary Status category 6
(critically endangered). This species has the
highest priority rating of all suiformes, and is considered to be amongst the
most endangered of all mammals. Pygmy hogs are now reduced to only two known,
isolated populations in the few remaining tall grasslands of north-western
Assam. These are in the Manas Wildlife Sanctuary (391 sq km) and its buffer
reserves, and in the small Barnadi Wildlife Sanctuary (26.6 sq km). The size
of these populations is unknown, though the Barnadi population may number
less than 50 individuals and the Manas population is unlikely to be more than
a few hundred individuals, and may be considerably less. Unfortunately, Manas
is also seriously threatened following the recent (February 1989) invasion of
the Sanctuary by an extremist faction of the All Bodo Student's Union (ABSU),
who have wrested control of a large part of the core area and facilitated the
influx of large numbers of wildlife and timber poachers. The principal
recommendations for this species are: 1) the immediate return of control of
the Sanctuary to the relevant authorities by any possible means, and the
restoration and enhanced future protection of this area; 2) the early
initiation of field status surveys designed to: (a) determine the species'
current distribution and priority requirements in the environs of Manas, (b)
identify any other possibly surviving, remnant populations elsewhere in the
region, and c) identify suitable sites for possible future reintroductions;
3) the establishment of a properly structured captive breeding program, both
as a safeguard against the species' possible imminent extinction and as a
source for future reintroductions; and 4) the initiation of a medium to long
term field studies on the species' behavioral-ecology and habitat management
requirements. Introduction The pygmy hog is the
world's smallest suid and is therefore a potentially extremely valuable
genetic resource. It is also one of the most useful indicators of current
wildlife habitat management practices - particularly the effects of
widespread, too-frequent burning and other exploitative and degradative
pressures - in the few remaining tall grasslands of the northern Indian
subcontinent (Oliver, 1980, 1981, 1984; Bell and Oliver, 1991a). S. salvanius is a monotypic
species (Groves, 1981; Grubb and Groves, this vol.), which is sympatric with S. scrofa throughout its limited known
range. Relatively few characters other than the extreme reduction in body
size (i.e. males c. 65 cm head + body length, c. 25 cm shoulder height, c.
8.5 kg wt.; females somewhat smaller; Mallinson, 1977; Oliver, 1980) are
truly diagnostic, though the vestigial tail (c. 3cm) and possession of only
three pairs of mammae are specific characters. In addition, there are some
important changes in the proportions of the body in comparison with other members
of the genus (e.g. reduction in the size of the forequarters, ears and length
of the facial skeleton), which effect a marked streamlining of the body.
These factors, together with its diminutive size, enable pigmy hogs to move
with great rapidity through their extremely dense, early successional, tall
grassland habitat, to which they are evidently restricted and supremely well
adapted. Link to Fig. 11:
Approximate former and present known range of the pygmy hog, Sus salvanius. Former and Present Distribution Most records of this
species appertain to the narrow alluvial tract known as the 'terai' or 'duars', which extends south of the Himalayan foothills from
north-eastern Uttar Pradesh in the east, through southern Nepal and northern
West Bengal to north-western Assam and adjacent parts of extreme south Bhutan
(Fig. 1). The presence of pygmy hogs has never been confirmed from
north-eastern Assam or southern Arunachal Pradesh, though it is possible that
they occur there (Oliver, 1981; Pandya, 1990). However, the species is known
to have occurred in some areas south of the Brahmaputra River in south and
south-eastern Assam. Contemporary records from the latter areas include eyewitness
reports in the Goalpara District of south-west Assam in the late 1950's/early
1960's (Oliver, 1979a, 1980) and from the Surma Valley in Cachar District,
south-east Assam, where one of us (SDR) saw a freshly killed animal in 1968.
No trace of the species' continued existence in these areas was found during
the course of brief surveys in 1977 and 1978 (I. K. Bhattacharyya, pers.
comm.), though their former occurrence in the Cachar region lends credence to
the occasional, unconfirmed reports of their recent occurrence in parts of
north and north-east Bangladesh (Oliver, 1984, 1985). Unfortunately, the
species is almost certainly extinct over most of its known or presumed recent
range in the terai and duars regions. Occasional rumors of
pygmy hogs in south-eastern Nepal, for example, have not been verified,
despite repeated attempts to locate them (Griffiths, 1978). A U.S. expedition
from the Hormel Institute spent four weeks searching unsuccessfully for pygmy
hogs in 1964 (T. Reed, pers. comm.). A University of East Anglia expedition
team also failed to find any trace of these animals during a six-month survey
of tall grasslands in south-east Nepal, and concluded that remaining habitat
was so limited that it was unlikely that the species survived there (Rands et al., 1979). A similar, three months
survey of all remaining grassland in the reserve forests, wildlife
sanctuaries and national parks of northern Bangladesh, northern West Bengal,
north-western Bihar, north-eastern Uttar Pradesh and south-western Nepal in
1984, also failed to reveal any definite evidence of surviving animals,
though several new populations of the closely-associated hispid hare, Caprolagus hispidus, were described
(Oliver, 1984; Bell and Oliver, in press; Bell et al, in press). All recent,
confirmed reports of this species therefore originate from the reserve forest
belt of north-western Assam, where at least seventeen pigmy hogs were
captured in the vicinity of the Barnadi Reserve Forest, in Darrang District,
in March/April, 1971; most of which were retained for a captive breeding
venture on neighboring tea estates. The circumstances surrounding this event,
which was hailed by several authors (e.g. Tessier-Yandell, 1971; Mallinson,
1971) as the 'rediscovery' of the species, were made rather more remarkable
by the coincidental first reporting of the species in the Manas Wildlife
Sanctuary, approximately 60 km west of Barnadi. The species was subsequently
reported from a number of separate areas in the environs of the Manas
Sanctuary (Deb Roy, unpubl.), and in the Khalingdaur Reserve Forest,
approximately 5km east of Barnadi (Ranjitsinh, 1972). The continued
occurrence of small numbers of pygmy hogs in Barnadi R.F. was confirmed
during the course of a two months survey of the reserve and unclassed state
forests of north-western Assam in 1977, which also revealed the recent (c.
1975) extinction of the population in Khalingdaur R.F., but their continued
existence in a number of other areas in the region, namely: Subankhata R.F.,
Darranga R.F., Corromore U.S.F., Rowta R.F., Balipara R.F. and Gohpur R.F.
(Oliver, 1979a, 1980). However, all of these other populations were reported
to be of small size and highly susceptible to encroachment and exploitation
pressure, and all of them are known, or believed likely to have been lost
since that time (Oliver, 1981, 1984; Deb Roy, in litt.; P. Lahan, pers. comm.). Accordingly, by the mid-1980's,
the only known, viable population (i.e. undoubtedly surviving and of presumed
reasonable size) was in the Manas Sanctuary and the contiguous Koklabari and
Manas Reserve Forests. In 1981, the Barnadi Reserve Forest was finally
upgraded to a Wildlife Sanctuary for better protection of the pygmy hog and
the hispid hare, and small numbers of both species have recently been
confirmed as surviving in this area (S. K. Sharma, pers. comm.; N. C. Kalita,
pers. comm.; Oliver, 1990a, 1991). Habitat, Ecology and Behavior Adult male pygmy
hogs are distinguished by their relatively larger size, more robust
appearance and exposed tusks. They are usually 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 social units of (usually) four to six
individuals, comprising one or more adult females and accompanying immatures.
Reproduction is strongly seasonal, with almost all recorded data indicating a
single, well defined birth peak, which coincides with the onset of the
monsoon (i.e. in late April and May in western Assam). Litter size varies
from two to six, but is usually three to four (Mallinson, 1977; Oliver,
1979b, 1991). The species is also unusual amongst the suids in that nests are
constructed and utilized by both sexes at all times of the year, and
nest-building is not, therefore, associated only with farrowing or inclement
weather (Oliver, 1980). All recent data
indicate that this species is dependent on early successional riverine
communities, typically comprising dense tall grasslands, commonly referred to
as 'thatchland', but which, in its pristine state, is intermixed with a wide
variety of herbaceous plants and early colonizing shrubs and young trees.
These grasslands, or 'mixed thatch-scrub', are a feature of the successional
continuum between primary colonizing grasses on the new alluvium deposited by
changing water courses, through to deciduous riverine forests and, in drier
areas, the Sal (Shorea robusta)
forest climax vegetation. Tall grasslands may also form an understory during
later stages of this succession, particularly near water courses, or in
forest clearings and abandoned cultivation and village sites. In relatively
undisturbed areas, the grasslands are maintained by prolonged inundation
during the monsoon and/or by periodic burning. In disturbed areas, they are
maintained by regular burning, grazing pressure, and/or regular harvesting of
the thatch grasses for roofing and domestic animal fodder. There are many
species of tall grasses, which dominate in different situations. The most
important of these communities for pigmy hogs are those which tend to be
dominated by Saccharum munj, S. bengalensis, Themida villosa and Narenga
spp., which form characteristic associations of 2 to 3m height, during
secondary stages of the succession on well drained ground. These communities
are not, therefore, maintained by prolonged inundation, though they may be
maintained by periodic burning. However, as they also include some of the
most commercially important thatching grasses, most of these areas (including
many of those in wildlife sanctuaries and national parks) are harvested
annually and virtually all of them are subject to wide-scale annual (in some
areas, twice-annual) burning. Most of this burning is conducted at the
beginning of the dry season (i.e. in December or early January), in order to
preclude the possibility of later, uncontrolled 'hot' burns, which are far
more destructive. As a result, however, the regularly burnt grasslands are
also characterized by the relatively uniform growth of a few, fire-resistant
species and, hence, a chronic reduction in species' diversity and the quality
and carrying-capacity of this habitat for many dependant animal species. Threats to Survival The recent and
continuing decline in the distribution and numbers of pygmy hogs is directly
attributable to the loss and degradation of habitat to human settlements,
agricultural encroachment, commercial forestry and flood control schemes; the
latter as a result of the disruption of natural successions and the
replacements of former grasslands by later stage communities or other
developments. In Assam, as elsewhere, most former habitat has been lost to
settlements and agriculture following the rapid expansion of the human
population. However, this process has been exacerbated by high levels of (mostly
illegal) immigration of Bengali, Bangladeshi and Nepali peoples, thereby also
producing problems of civil unrest amongst Assamese ethnic groups. These
factors have put additional pressure on what little wildlife habitat remains,
and have resulted in the loss of at least two known populations of these
animals in recent years; i.e. those in Corromore Unclassed State Forest,
which was occupied by immigrant settlers from Nepal in 1978/79, and those in
Gohpur Reserve Forest which was swamped by illegal immigrants from Bangladesh
in 1979/80 (D. K. Lahiri-Choudhury, pers. comm). In these, as in
other parts of north-western Assam, the surviving grasslands are reduced to
small, discrete patches within declared reserve boundaries, where they are
mostly subject to continued attrition or exploitation through commercial
afforestation programmes, over-grazing by domestic herbivores and/or thatch
grass harvesting. Virtually all remaining grasslands are therefore burnt
every year, either by Forest Department personnel or by herdsmen and thatch
collectors from neighboring settlements. This burning is extremely
prejudicial to the survival of the hog, through the short-term loss of cover
and other resources, and the resulting ecological instability, loss of
species' diversity and consequent reduction in the carrying capacity of this
habitat for dependant (non-grazing) animals. In drier areas, the interval
between the burning (usually in late December or January) and the regrowth of
vegetation following early rains (usually in April or May) may be as long as
three to four months. During this period, the hogs are either entirely
dependent on any habitat left unburnt, mostly by chance or, if burning is
particularly severe, are forced to seek cover elsewhere (e.g. on neighboring tea
estates). In either event they are liable to be killed by hunters, whose
activities are facilitated by the enforced concentration of game in any
remaining cover during the post-burning period. In the Barnadi Reserve Forest
in 1977, for example, village hunters accounted for at least five (14%) of
the total estimated population of about thirty-five pigmy hogs (Oliver,
1979a, 1980). A combination of
these factors has almost certainly resulted in the loss of all of the
recently known (i.e. post-1971), small populations of these animals in the
reserve forests of north-western Assam. These losses include Khalingdaur
Reserve Forest, where pigmy hogs were reported to have become extinct by
1975/1976 following the replacement of some habitat by hardwood plantations
and the repeated burning of all of the remaining grasslands by herdsmen.
Wide-scale burning in connection with commercial thatch concessions is
thought to have accounted for the loss of small populations in Subankhata,
Darranga and Rowta Reserve Forest some time between 1978 and 1980. The
population in Barnadi was also feared lost following particularly extensive
burnings in 1980 and 1981 (Oliver, 1981). However, a recent (1990) visit to
this area provided confirmation of subsequent reports that small numbers of
these animals survived, following the upgrading of Barnadi from a Reserve
Forest to a Wildlife Sanctuary in August 1981, the subsequent cessation of
all commercial forestry practices, the eviction of squatters and improved
protection (patrolling) against poaching and grazing of domestic herbivores
(P. C. Das, pers. comm., N. C. Kalita, pers. comm., Oliver, 1990a). These losses
strongly reinforced the overwhelming importance of the largest and, by the
early to mid-1980's, only known surviving population in the Manas Wildlife
Sanctuary. Moreover, the deleterious effects of wide-scale annual burning on
the tall grasslands in Manas are considered less severe than in the reserve
forests, owing to the absence of the associated exploitative practices, the
deliberate management policy of early 'patch-burning', and the rapid regrowth
of vegetation consequent of condensation and a high water table. Given the
relatively large size of the Sanctuary (391 sq km) and contiguous reserve
forests, which incorporate several large grasslands, some inter-population
dispersal is possible, and a single catastrophic event, such as a major
conflagration, is unlikely to eliminate the entire population of hogs, as has
apparently happened elsewhere. Nonetheless, the
survival of this species remains crucially dependant on the future of the
Manas Sanctuary itself. Unfortunately, this is far from assured, given the
continued civil unrest and other, mostly political, problems relating to the
high levels of illegal immigration and a strong separatist movement in Assam.
Recent threats to the Sanctuary have included the proposed construction of
two dams on the Bhutan side of the Manas River, to supply hydro-electric
power, flood control and water for irrigation schemes on the north bank of
the Brahmaputra River. This plan was abandoned in 1986, following strong
national and international opposition, but in February 1989, an equally
serious threat became manifest when armed extremists of the All Bodo
Student's Union (ABSU) invaded the Sanctuary and killed several guards,
looted and burnt rest houses and other property, and allowed the entry of
numerous wildlife and timber poachers. This and subsequent attacks on the
Sanctuary staff and property was justified on the basis that the Manas area
was part of the homeland of the Bodos, one of the largest ethnic minorities
in Assam, but had been taken from them during the British rule. In fact,
however, Manas is being used as a refuge by militant extremists who shelter
in the Sanctuary following acts of hostility and sabotage elsewhere in the
region. At present, most of the core area, particularly the 120 sq km western
sector, continues to be controlled by the extremists and therefore remains
out of the control of the relevant authorities. The damage perpetrated by
poachers and the rebel tribals is not thought likely to have had a major
negative impact on the pygmy hog population as yet, but the future of the
whole area is now in jeopardy (Deb Roy, unpubl.; Oliver, 1990b). Conservation Measures Taken The pygmy hog is
included on Schedule 1 of the Indian Wild Life (Protection) Act (Government
of India, 1972) under the terms of which it is accorded maximum protection.
However, this Act was not ratified by the State of Assam until January 1977, and
it has proven entirely ineffective in protecting this species in the absence
of any legal protection of its habitat over the majority of its recent known
range in the reserve forests of N.W. Assam. In 1981, the Barnadi Reserve
Forest was upgraded to a Wildlife Sanctuary for the better protection of the
pygmy hog and the hispid hare, and small numbers of these species are now
known to survive there despite earlier fears that they were both extinct in
the area by that time. The species also survives only in the Manas Wildlife
Sanctuary and its buffer reserve forests. However, its habitat remains
unprotected in latter areas, where commercial forestry operations pose a
continuing threat to its survival. The Manas Sanctuary was one of the first
sanctuaries to be designated in (1973) as a Tiger Reserve, and its boundaries
were extended to a total area of 2,837 sq km in 1980. In recognition of its
international significance, Manas was also one of the first wildlife areas in
India to be designated by Unesco (in 1986) as a World Heritage Site. However,
it is also included on the IUCN list of the World's Threatened Protected
Areas (J. Thorsell, pers. comm.). The pygmy hog is
included on Appendix 1 of the 1973 Convention of International Trade in
Endangered Species of Wild Fauna and Flora (CITES), so that trade in it or
its products between acceding nations is subject to severe restriction, and
trade for primarily commercial purposes is prohibited. However, international
trade is not considered an issue for this species, or to have materially
influenced its present conservation status. The species is listed as
'Endangered' in the IUCN Red List of Threatened Animals (1988), and was
included in the first (1984) IUCN/WWF listing of the twelve most threatened
animal species (Anon, 1985). It is also included in the current, provisional
list of World Heritage Species (S. Edwards, pers. comm.). Current
understanding of the species' recent history, distribution, present status
and future management needs are based largely on the field surveys conducted
in 1977, 1981 and 1984, referred to above (Oliver 1979a,b, 1980, 1981 and
1984), and on observations are records appertaining to the captive animals on
tea estates (Mallinson, 1971, 1977) and in the Manas Sanctuary (Deb Roy, unpubl.).
A three-point 'Action Plan for the Pigmy Hog', submitted to the relevant
authorities in the Assam States and Indian Central Governments by the
IUCN/SSC Pigs and Peccaries Specialist Group, was agreed in full in December
1987 but, owing to the continued high levels of civil unrest in north-western
Assam, this has yet to be implemented. A duly modified, and extended version
of this Plan is outlined below. Captive Breeding Despite the
relatively large number (i.e. >40) of pigmy hogs taken into captivity on
tea estates in north-west Assam between 1971 and 1976, and the relatively
large number of captive births (>45) recorded during this period
(Mallinson, 1977), all of this stock has since died out. These losses include
small numbers of animals supplied to the Assam State Zoo, Guwahati, and
Zurich Zoo, Switzerland (K. C. Patar, pers. comm.; Schmidt et al., 1978; Oliver, 1980; Schmidt,
unpubl.). Small numbers of pygmy hogs were also maintained in a compound in
the Manas Wildlife Sanctuary in the mid-1980'. Several litters were born to
these animals, but no young reared and all of the adults eventually escaped
or were released. A further ten individuals (six caught in 1988 and four in
1989) were captured in Manas and placed in a larger (1.25 ha) enclosure in
tall grassland in Bansbari Range, Manas, though the subsequent history of
these animals, is poorly known owing to the difficulty of observing them in
such a (relatively) large, densely vegetated enclosure, difficulty of access
during the current crisis, and the fact that the enclosure has been damaged
by wild elephants and rhinos on at least two occasions. In any event, there
were no pygmy hogs left in this enclosure by late 1991/early 1992 (P. Lahan,
pers. comm.). Additional Remarks The pygmy hog is
thought to be sole host of the pigmy hog sucking louse, Haematopinus oliveri, which, owing to the status of its host, is
also accorded 'Endangered' categorization in the IUCN Invertebrate Red Data
Book (Wells et al., 1983). Any conservation
measures designed to protect the habitat of the pygmy hog are certain to
benefit a wide variety of other seriously threatened species, including the
hispid hare, Caprolagus hispidus,
and the Bengal florican, Houbaropsis
benghalensis, both of which species also have their largest surviving
populations in the Manas Sanctuary. As it is by far the
smallest suid, the pygmy hog is a potentially extremely useful and valuable
genetic resource, with obvious possibilities for use in biomedical research
and for the further domestication of one of the man's most important sources
of terrestrial animal protein. Conservation Measures Proposed:
An Action Plan In line with
currently available information on the critical status of this species, and
the terms and objectives of India's National Wildlife Action Plan (Government
of India, 1983), the following objectives and actions are strongly
recommended for immediate implementation. However, it is recognized that the
survival of this species is intimately linked with the restoration of the
Manas Wildlife Sanctuary by the removal of illegal occupants and the enhanced
future protection of this Sanctuary and its buffer reserve forests, and that
any such actions are of paramount priority and urgency. Objectives: 1. To promote whatever actions are necessary
to restore the Manas Wildlife Sanctuary and its buffer reserves, and to
assist the enhanced future protection of that area. 2. To help to ensure the survival of the pygmy
hog into perpetuity by the promotion and implementation of those
activities/projects specified in the Action Plan, or such others as may be
identified in the future. 3. To facilitate an enhanced understanding and
appreciation of this species, its potential importance as a genetic resource
and as a model for the enhanced future management of tall grasslands in the
north Indian sub-continent. Priority Projects: 1. Conduct
field status surveys of the Barnadi and Manas Wildlife Sanctuaries (the
latter to include the adjacent Koklabari, Kahitama, Panbari and Manas Reserve
Forests) in order to assess this species' present distribution, status and
immediate management requirements in these areas. 2. Conduct field status surveys of selected
tall grasslands within the known, or postulated recent range of this species,
with a view to the identification and protection of any possibly surviving
populations elsewhere, and the assessment of selected areas for the future
reintroduction of translocated or captive-bred animals. Areas
to be investigated should include: Pochu and Mochu Reserve Forests, Goley
Game Reserve, Neuri Wildlife Reserve and Khaling Reserve Forest in southern
Bhutan; Subankhata and Darranga Reserve Forests, Sonai-Rupa and Nameri
Wildlife Sanctuaries in north-western Assam; and Pakkui, Lali, Dibru
Saikhowa, D'Ering Memorial and Namdapha Wildlife Sanctuaries in southern
Arunachal Pradesh. Selected areas in south-eastern Assam, north-eastern
Bangladesh and extreme south-western Nepal may also merit further
investigation in this context. 3. Establish
a properly structured, captive breeding program. This
Program should include the following objectives: a) to serve as a safeguard
against the (not improbable) early extinction of the species in the wild
state; b) to serve as a source of animals for reintroduction to selected,
protected sites within its recent known habitat in north-western Assam and
elsewhere; c) to serve as a means of obtaining detailed information on the
species' life history, reproductive biology and social behaviour, much of
which information would be impractical to obtain from studies of wild animals
(also see below); and d) to serve as a conservation education, captive
breeding and field research training facility. This program should be
initiated in Barnadi (if possible with a corollary project in Manas), but
should include extensions to other reputable breeding centers in India or
elsewhere at the earliest opportunity. 4. Conduct
detailed studies of the behaviour and ecology of the pygmy hog, with
particular reference to the establishment of management criteria for the
enhanced protection of the wild population. These
studies should be conducted in Manas (with its more extensive range of early
successional grasslands and grassland dependent species) and in Barnadi (where
field conditions are easier) and should be continued for at least two years,
but preferably three to four years. These studies should include related
investigations into the general ecology of the tall grasslands the effects of
current management policies, particularly dry-seasonal burning, with a view
to the development of strategies designed to maintain the integrity of these
grasslands and optimal species' diversity. Manas is ideally suited for this
purpose since it supports a variety of different tall grass communities, and
representative populations of a larger number of major (including Schedule 1)
species of herbivores than any other area in the Indian sub-continent. Acknowledgements Grateful thanks are
extended to numerous officials in the Wildlife Sections of the Forest
Department, Govt. of Assam, and the Ministry of Environment & Forests,
Govt. of India, who have provided much useful information or otherwise
facilitated the compilation of this Plan. We would also wish to express our
sincere appreciation for the invaluable assistance provided to us at various
times by many other individuals and numerous other governmental and
non-governmental institutions in India and elsewhere. We are thankful to Paul
Vercammen and Peter Cuypers for preparing the distribution map. The continued
support of the Wildlife Preservation Trust is also gratefully acknowledged. References Anon 1971. Pigmy hog and hispid hare. Oryx, J.
Fauna Preserv. Soc., XI (2-3): 103-107. Anon 1985. Choosing the 24 most endangered
species. Newsletter, Species Survival Commission, 5: 17-23. Bell, D. J. and Oliver, W. L. R. 1991. The
burning question, and other problems relating to tall grassland management
and the conservation of endangered species in the northern Indian sub-continent.
(In press). Bell, D. J., Oliver, W. L. R. and Ghose, R. K.
1991. The hispid hare Caprolagus
hispidus. In: J. A. Chapman and J. E. Flux (eds): Rabbits, Hares and
Pikas: Status Survey and Conservation Action Plan, IUCN, Gland, Switzerland:
128-136. Government of India 1972. The Indian Wildlife
(Protection) Act, New Delhi. Government of India 1983. National Wildlife
Action Plan. Dept. of Environment, New Delhi: 28pp. Griffith, L. D. 1978. The search for the pigmy
hog in Nepal. Nature Ann., Nepal Nature Conserv. Soc.,11:41-45. Groves, C. P. 1981. Ancestors for the Pigs:
Taxonomy and Phylogeny of the Genus Sus.
Tech. Bull. No. 3, Dept. Prehistory, Res. Sch. Pacific Studies, Australian
Nat. Univ.: 96pp. IUCN 1988. The IUCN Red List of Threatened Animals.
IUCN, Gland, Switzerland and Cambridge, U.K. Mallinson, J. J. C. 1971. The pigmy hog, Sus salvanius (Hodgson) in northern
Assam. J. Bombay Nat Hist. Soc., 68 (2): 424-433. Mallinson, J. J. C. 1977. Breeding of the
pigmy hog, Sus salvanius (Hodgson)
in northern Assam. J. Bombay Nat. Hist. Soc., 74 (2): 288-289. Oliver, W. L. R. 1979a. The doubtful future of
the pigmy hog and the hispid hare: pigmy hog survey report, part I. J. Bombay
Nat. Hist. Soc., 75 (2): 341-372. Oliver, W. L. R. 1979b. Observations of the
biology of the pigmy hog (with a footnote on the hispid hare): pigmy hog
survey report, part II. J. Bombay Nat. Hist. Soc., 76 (2): 115-142. Oliver, W. L. R. 1980. The Pigmy Hog: the
Biology and Conservation of the Pigmy Hog, Sus (Porcula) salvanius, and the Hispid Hare, Caprolagus hispidus. Jersey Wildl.
Preserv. Trust, Spec. Scien. Rep. No. 1: 80pp. Oliver, W. L. R. 1981. Pigmy hog and hispid
hare: further observations of the continuing decline (or, a lament for
Barnadi, and a good cause for scepticism). Dodo, J. Jersey Wildl. Preserv.
Trust, 18: 10-20. Oliver, W. L. R. 1984. The distribution and
status of the hispid hare, Caprolagus
hispidus: the summarised findings of the 1984 pigmy hog/hispid hare field
survey in northern Bangladesh, southern Nepal and northern India. Dodo, J.
Jersey Wildl. Preserv. Trust, 21: 6-32. Oliver, W. L. R. 1985. The distribution and
status of the hispid hare (Caprolagus
hispidus), with some additional notes on the pigmy hog (Sus salvanius) - a report on the 1984
field survey. (Unpubl.) rep. to Wildlife Preservation Trust: 94 pp. Oliver, W. L. R. 1990a. A reprieve for
Barnadi. (Unpubl.) rep. to IUCN: 3pp. Oliver, W. L. R. 1990b. The troubles in Manas.
(Unpubl.) rep. to IUCN: 5pp. Oliver, W. L. R. 1991. Monograph on the pigmy
hog, Sus salvanius. In: H.
Fra‰drich and H.-G. Klos (eds.), Proc. of the Pigs and Peccaries Workshop at
Zoo Berlin, 12-15th July 1990: Bongo, Berlin: 21-38. Pandya, N. P. 1990. Report on an initial
survey of pigmy hog, Sus salvanius,
and hispid hare, Caprolagus hispidus,
and their habitat in Arunachal Pradesh, India during April 1990. (Unpubl.):
25pp. Rands, M., Brown, P. and Newton, P. 1979.
University of East Anglia Nepal Expedition, 1978/1978. (Unpubl.): 79pp. Ranjitsinh, M. K. 1972. A note on the future
conservation plan for the pigmy hog (Sus
salvanius) and hispid hare (Caprolagus
hispidus; Pearson, 1839). (Unpubl.) D.O. No. 682/DSF 1023/72, Govt. of
India. Schmidt, C. R., Mallinson J. J. C. and
Weilenmann, P. 1978. International co-operation for captive breeding of the
pigmy hog, Sus salvanius. Int. Zoo
News, 25/3 (150): 28-31. Tessier-Yandell, J. 1971. The pigmy hog, Sus salvanius. Cheetal, 14 (3): 23-28.
Wells, S. M., Pyle, R. M. and Collins, N. M.
1983. The IUCN Invertebrate Red Data Book. IUCN, Gland: 365-367. |
|
Next: Chapter 5.4 – The
Javan Warty Pig |