Sus verrucosus, Linnaeus, 1758

Don E. Wilson & Russell A. Mittermeier, 2011, Suidae, Handbook of the Mammals of the World – Volume 2 Hoofed Mammals, Barcelona: Lynx Edicions, pp. 248-291 : 287-288

15.

Javan Warty Pig

Sus verrucosus

French: Sanglier de Java / German: Java-Pustelschwein / Spanish: Jabali de Java

Taxonomy. Sus verrucosus Boie, 1832 ,

Java.

The ancestry of this species has been traced back to some fossil pig species of Java, which combined with phylogenetic data suggests that the S. verrucosus lineage has evolved on Java for approximately two million years. Two subspecies are recognized.

Subspecies and Distribution.

S. v. verrucosusBoie, 1832 — W & CJava; extinctonMaduraI.

S. v. bloucht Groves, 1981 — Bawean I.

Descriptive notes. Head—body 90-190 cm, tail 15-25 cm, shoulder height 70-90 cm; weight 35-150 kg. Compared to other species of Sus the Javan Warty Pig is characterized by great elongation of the face, and more pronounced sexual dimorphism. Male S. verrucosus can be easily distinguished from other species (at least when seen from nearby) by the presence of warts. Observations from two captive S. verrucosus indicate that warts start to grow when youngsters are 17 months old and weigh approximately 25-35 kg. The two pig species on Java are externally quite similar, and it will often be difficult to determine the species when an animal is seen at a distance, or when it is a female (which lack the warts). Compared to the Eurasian Wild Pig (S. scrofa ), S. verrucosus gives the impression of having a very large, heavy head, at least in adult males. Males of S. verrucosus are much larger than females (c. 90 kg for males as opposed to 45 kg for females). Such pronounced sexual dimorphism is not found in S. scrofa , where the males weigh about the same as the S. verrucosus males, but the females are much heavier than S. verrucosus females. Pelage coloration varies greatly in both species. Generally S. verrucosus appears somewhat reddish, but some individuals look quite black from a distance. The hair on the crown and the mane on the back of the neck are usually paler, often reddish-orange and occasionally approaching blond. In S. verrucosus of all sexes and ages the hair on the belly is predominantly white or yellowish, contrasting with the darker pelage on the upper part of the body. S. scrofa on Java are most often black or grizzled, but reddish-brown individuals are sometimes encountered. The mane is usually black and the belly hairs are also dark, not contrasting with the pelage above. The individual hairs in S. scrofa are of a single type: black with a yellowish band or (when worn) tip. In S. verrucosus there are two hair types intermixed: shorter red or yellow hairs with black tips, and longer black ones. The coloration of piglets in the two Javan pig species differs as well. S. scrofa piglets are longitudinally striped, black-brown and whitish to fawn; the striping is very conspicuous. In S. verrucosus, on the other hand, the striping of piglets is very faint and may be difficult to discern in the field. The shape of the lower canines in male pigs is another good indicator of their specific identity. If a cross section is taken near the base, in S. scrofa the inferior surface is narrower. In S. verrucosus it is as broad as the enamel-less posterior surface. If the width of inferior surface is expressed as a percentage of the posterior surface, for S. scrofa this ranges between 61:5% and 109-1%, and for S. verrucosus it ranges between 113:3% and 161:5%. The canines in females are also distinctive. In S. scrofa they are fairly large: the greatest diameter of the upper canine varies from 16-8 mm to 18-2 mm, and of the lower from 14 mm to 17 mm, overlapping the male range. In S. verrucosus the canines of females are much smaller, the upper measuring 9-3-11-5 mm, the lower 7-3— 10 mm. The race blouchi is distinguished from the nominate subspecies by its smaller size, the relatively low occiput, the red color of the pale hairs in the coat, and the red mane.

Habitat. The Javan Warty Pig occurs both in cultivated landscapes and in teak (7ectona grandis) forest plantations, interspersed with lalang grasslands (/mperata cylindrica), brush, and patches of secondary forest, restricted to elevations below about 800 m. The reasons for this are not known, but it might be because the pigs are unable to tolerate low temperatures. They evidently prefer secondary or disturbed forests, though they are also often found near the coasts in remnant patches of mangrove and swamp forest. They are rare in the few remaining lowland primary forests and in areas with high human populations where otherwise suitable habitat is fragmented and surrounded by agricultural land. However, they do feed on crops, making nocturnal raids on fields of corn and cassava. As with S. scrofa , the species is widely persecuted for such depredations. The two species appear to avoid each other. In the 1920s, their abundance was thought to be similar, but only one species was generally found in a given location. S. scrofa appeared to be better adapted to agricultural areas and heavily degraded forests, and S. verrucosus more restricted to woodlands.

Food and Feeding. Ecological information about S. verrucosus is rare because when the species wasstill relatively common, extensive descriptions of feeding and breeding ecology did not differentiate between S. verrucosus and S. scrofa . One account from 1928 describes their ecological similarities: both species feed on a range of animal and plant foods, including fallen fruits, roots, worms, and insects. They are particularly partial to ripe rice, making them a feared agricultural pest.

Breeding. The gestation period is thought to be about four months, and 3-9 young are born. Most births reportedly occur in the rainy season, from January to March, in a large nest made by the female out ofleaflitter. According to a recent informant, females with young are mostly seen between August and December.

Activity patterns. There is little known about activity patterns of S. verrucosus. Interview surveys on Java in 2003 suggest that the species is mostly nocturnal, with several respondents reporting that damage to rice fields almost exclusively happened at night. It could be that a shift from generally diurnal activity patterns in pigs to nocturnal ones is because of the very high hunting pressure on the species.

Movements, Home range and Social organization. No estimates of home range or population density are available. Historically, group sizes of up to 20 animals were reported, though most recent records refer to groups of no more than six individuals during the breeding season and fewer at other times.

Status and Conservation. Classified as Endangered on The IUCN Red List. It is now restricted to several isolated areas on mainlandJava. The Javan Warty Pig is endemic to the islands ofJava, Madura, and Bawean in Indonesia. It occurs alongside S. scrofa vittatus, but it appears that the two species avoid each other and attain their highest densities where the other speciesis absent. S. verrucosus was widespread on Java as recently as 1982, but is now absent from most of the island and survives only in highly fragmented populations. A Java-wide, interview-based survey in 2003 found that there were about ten areas on Java and Bawean where S. verrucosus populations survived, although other small groups may have existed elsewhere. These include remnant and low density populations in west Java in the areas between Malingping and Rangkasbitung, and between Sukabumi and the coastal nature reserves of Cikepuh. S. verrucosus is very rare near Purwakarta. Several small populations remain near and south of Garut, with a few reported sightings of S. verrucosus in 2002 and just before. Around Majalengka and towards Sumedang, interviewees reported recent killings of S. verrucosus, but the species is now much rarer than in the past. A population of S. verrucosus still remains east of Tasikmalaya towards Ciamis, although people consider S. verrucosus to be rare in comparison to S. scrofa . Several interviewees reported recent sightings of S. verrucosus from the area around Cilacap, Cipatujuh, and Nusa Kembangan, including some from the Nusa Kembangan Nature Reserve off Cilacap, but the species seems to be rare and fragmented into small populations. The only areas where S. verrucosus reportedly remained common were around Subah, where animals were generally seen in small groups of 1-2 individuals and groups of 4-6 during the mating season, and around Blora and Bojonegoro. In the latter area, group size had reportedly declined from 10-20 to only 1-3. No recent records of S. verrucosus exist from Madura Island, and the species is considered extirpated there. On Bawean Island, the only area where the subspecies blouchi occurs, the species is now very rare, and possibly already extirpated. There are no estimates of overall population size, but the species has shown a rapid population decline in recent decades. Compared to a survey conducted in 1982, 17 of the 32 populations (53%) are extirpated or have dropped to low encounter rate levels. [tis thought that the population decline observed in this species is primarily caused by a decline in suitable habitat, especially of stands of teak forest or similar forest plantations, and by high hunting pressure. These animals are killed both by sport hunters and by farmers protecting their crops. Many animals are killed by poisoning. As yet unpublished reports of the recent dramatic reduction in numbers, possibly resulting in the extirpation of subspecies blouchi on Bawean Island have been attributed to correspondingly increased hunting pressure following the recent settlement of Christian immigrants from Sumatra; these animals were previously left largely unharmed by the predominantly Muslim inhabitants. Competition from and hybridization with the Eurasian Wild Pig (S. scrofa ) has been speculated as a further threat to S. verrucosus, especially in areas where human-induced habitat changes favor S. scrofa . Recent DNA analysis of one S. verrucosus specimen suggested high levels of inbreeding in the species compared to other Sus species , but no evidence of introgression from S. scrofa was found. Further genetic studies on more samples are needed to assess potential conservation implications of both inbreeding and hybridization.

Bibliography. Bartels (1937, 1940, 1942), Blouch (1983, 1988, 1993), Blouch & Groves (1990), Franck (1936), Groves (1981), Hardjasamita (1987), Huffman (2004), Nijman (2001, 2003), Olivier (1925, 1928), Semiadi & Meijaard (2004, 2006), Semiadi et al. (2008), Sody (1936, 1941a, 1941b).

Figures

On following pages 10 Phılıppıne Warty Pıg (Sus phı/ıppensıs) Mındoro Wany Png (Sus olıven) 12 Pılawın Bearded Pıg (Sus ıhoanobırbus). 13 Bearded Psg (Sus barbatus), 14 Sulawesı Wany Pug (Sus celebensıs) 15 Javan Wany Pıg (Sus venucosusl. 16 Eurasıan Wıld Pıg (Sus scrola) 17 Pygmy Hog (Porcııla salvımı)

Subspecies and Distribution. S. v. verrucosusBoie, 1832 — W & CJava; extinctonMaduraI. S. v. bloucht Groves, 1981 — Bawean I.