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Sus celebensisCelebes wild boar

By Nicole Noel

Geographic Range

Sus celebensis is found in the lower east portion of the oriental region and the upper west portion of the Australian region. Sus celebensis is common in the northern, central and eastern Sulawesi Island. Available evidence supports that this species formerly occured thoughout Sulawesi, as well as the neighboring islands of Selayer, Muna, Buton, Peleng, Lembeh and the Togain Islands. The species is now scarce in Southern Sulawesi and may also be extinct on the neraby Selayar due to the virtual deforestation of these areas. Wild pigs referred to as feral S. celebensis have been extensively introduced in Indonesia on the islands of Halmahera, Flores, Timor, Lendu, Simeuleu, and Nias Islands, and the domesticated forms of S. celebensis can be seen on the islands of Roti and Savur. (Macdonald, 1993)

Habitat

Celebes wild boars are reported to occur in a wide variety of habitats on the Indonesian Islands, including rainforests, swamps, high grassland terrains, and agricultural areas. They are found at altitudes up to moss forest at about 2300 m, but they prefer valleys. (Huffman, 1999; Parker, 1990)

  • Range elevation
    2300 (high) m
    7545.93 (high) ft

Physical Description

The coat of S. celebensis is often black in color with yellow and/or white hairs intermixed. Some specimens have been known to be reddish/brown. The ventral side lightens to a creamy off-white with age. There is always a dark dorsal stripe, and a yellow band that encircles the snout. Distinctive tufts of hair are found on the forehead. Piglets are born with five dark brown and six light horizontal stripes along the length of their bodies, which tends to go away after about 6 months of age. (Hooijer, 1969; Huffman, 1999; National Research Council, 1983; Parker, 1990)

Adult males develop three pairs of facial warts. The preorbital pair is the largest, but these do not reach their full size until the pigs are at least 8 years old. All the warts become larger with age. (Hooijer, 1969; Huffman, 1999; National Research Council, 1983; Parker, 1990)

The backs of Sulawesi warty pigs are short and slightly convex. These animals have relatively short legs, and a long tail that is simply tufted. Body length has been recored at 80 to 130 cm, and shoulder height at 70 cm. Adult males are larger than sows, averaging 60 cm at the shoulder. These swine can weigh any where from 40 to 70 kg. Recent forms are larger than the sub-fossil remains found in caves in Southern Sulawesi. (Hooijer, 1969; Huffman, 1999; National Research Council, 1983; Parker, 1990)

  • Range mass
    40 to 70 kg
    88.11 to 154.19 lb
  • Range length
    80 to 130 cm
    31.50 to 51.18 in

Reproduction

There have not been any studies of this behavior at this time but, it is part of the action plan proposed by the IUCN. (Macdonald, 1993)

Although information is lacking on this species, the mating system of the genus Sus is typically polygynous. Males are reported to compete for access to females, and are generally unable to effectively secure access to mates until they reach their full adult size. Adult males may have reproductive access to as many as 10 females, but around 3 is more typical. It is reasonable to assume that S. celebensis is similar to congeners in mating system. (Nowak, 1999; Nowak, 1999)

Although not reported in the literature, one might speculate that the warts found on males of this species, as secondary sexual characteristics, play some role in reproduction. These may be attractive to females, or they may function in competition between males.

Breeding may occur at any time in the year, but there is a peak in February, with most births occurring in April or May. Females build large nests made of grasses, leaves, branches and twigs, piled over a shallow depression of two meters. Unlike most ungulates, members of the genus Sus give brith to their offspring in a nest, where the offspring remain for some time. (Huffman, 1999; Macdonald, 1993; Nowak, 1999)

Although many important details on the reproduction of S. celebensis are lacking, the remainder of the genus Sus has well documented reproductive patterns. Females are reported to have an estrous cycle of approximately 21 days, during which the females are only sexually receptive for 2 or 3 days. Gestation ranges from 100 to 140 days. Piglets weigh from 500 to 1,500 g at birth, and are weaned in 3 to 4 months. It is likely that S. celebensis falls within this range of variation. (Nowak, 1999)

In the genus Sus, young often become independent of the mother prior to the birth of her next litter. However, female young may have a prolonged association with their mother. Females usually give birth about once per year.

Within the genus Sus, sexual maturity may be reached by a few months of age. However, most females don't breed until they are about 18 months old. Males, although capable of breeding at younger ages, are usually not able to secure access to mates until they reach their full adult size, around the age of 5 years. (Nowak, 1999)

  • Breeding interval
    These animals probably produce only one litter per year.
  • Breeding season
    This species does not have a strict breeding season, although most matings occur in February..
  • Range number of offspring
    1 to 8
  • Average number of offspring
    2-3
  • Average gestation period
    4-5 months
  • Average weaning age
    3-4 months
  • Range time to independence
    1 (high) years
  • Average age at sexual or reproductive maturity (female)
    18 months

Parental behavior in this species is not well documented. As part of the IUCN action plan, this area still needs to be looked in to and studied in more detail. (Macdonald, 1993)

In spite of lack of specific information on S. celebensis, it is possible to draw inferences about the species from patterns common in the genus and in other mammals.

Unlike many artiodactyls, pigs are born in a nest. They are somewhat altricial compared to other ungulates. The mother cares for her young, providing them with food (milk), protection, and necessary grooming. All that young pigs learn about life, they learn from their mothers. Male pigs are reported to be solitary except near the time of mating, and so do not typically participate in parental care. (Nowak, 1999)

In many species of Sus, females are known to maintain relationships with their mothers. Although not specifically reported for S. celebensis, it is possible that such relationships occur. These extended relationships may be responsible for the association of multiple females with their young which are sometimes seen. In such associations, females of unknown relatedness come together after their young are weaned to form larger social groups.

  • Parental Investment
  • no parental involvement
  • altricial
  • pre-fertilization
    • protecting
      • female
  • pre-hatching/birth
    • provisioning
      • female
    • protecting
      • female
  • pre-weaning/fledging
    • provisioning
      • female
    • protecting
      • female
  • pre-independence
    • protecting
      • female
  • post-independence association with parents

Lifespan/Longevity

Data are lacking on longevity in the wild, but most members of the genus Sus are thought to live a maximum of 10 years in the wild. Rarely has this species been raised in captivity outside Sulawesi, and as far as it is known, pure-bred animals have never been produced in captivity. The longevity of this species in captivity is greater than 9 years. (Macdonald, 1993; Nowak, 1999)

Behavior

There have been no detailed studies of the behavioral ecology of Celebes wild boars. Celebes wild boars are thought to be social. The basic social unit is the family group, 2 to 3 family groups associating in larger groups or herds. (Huffman, 1999; Parker, 1990)

Males of the genus Sus are thought to be mainly solitary, except during breeding. Some forms of physical aggression, including, leaning, shoving, and open mouth attacks have been reported. (Nowak, 1999)

Pigs are usually reported to be mainly crepuscular and nocturnal. Sus celebensis is therefore an exception, as it is mainly a diurnal forager. Other members of the genus have been reported to wander a long way seasonally, as different sources of food become available. Information on the specific distances traveled by S. celebensis is not available. (Huffman, 1999; Nowak, 1999)

Other members of the genus have been reported to construct a crude form of shelter or canopy from matted grasses. This apparently helps them remain cool. All members of the genus are thought to wallow in mud when able. (Nowak, 1999)

Home Range

The size of home ranges for members of this species has not been reported. However, within the genus, estimated home range sizes are 500 to 1000 hectares for females, and 1000 to 2000 hectares for males. (Nowak, 1999)

Communication and Perception

There is no information on the communication habits of the S. celebensis. However, as mammals, it is likely that they utilize some combination of visual, accoustic, tactile, and chemical communication.

Food Habits

Most feeding activity occurs during the daylight hours, with more activity in the early morning and late afternoon. Celebes wild boars are omnivorous and their diet consists of roots, fruits, leaves, shoots, carrion, and insects. (Huffman, 1999; Macdonald, 1993)

  • Animal Foods
  • carrion
  • insects
  • terrestrial non-insect arthropods
  • Plant Foods
  • leaves
  • roots and tubers
  • seeds, grains, and nuts
  • fruit
  • Other Foods
  • fungus

Predation

The only known predator of this species is humans through hunting. It is likely that there are other predators, however, as the striped pattern of young pigs is typically interpreted as a form of camouflage. (Huffman, 1999; Nowak, 1999)

  • Anti-predator Adaptations
  • cryptic

Ecosystem Roles

No information could be found on the specific ecosystem roles of S. celebensis. However, it is likely that their foraging behavior has some impact on local plant and insect communities. Because pigs root, it is likely that they help to aerate the soil. (Nowak, 1999)

Economic Importance for Humans: Positive

Wild piglets that are caught by villagers in Sulawesi are kept and are usually raised for slaughter for eating or sold at the local market. The Minahasa people consider wild pig meat to be superior to the domestic pork and are willing to pay 20 to 50% more for it. However, resources are insufficient to enforce controls on hunting and there are reports that organized commercial hunting is continuing even on designated reserves and national parks. Brief surveys of three villages markets in northeast Sulawesi concluded that about 2 to 20 wild pigs per week were being brought by these commercial hunters and slaughtered by butchers when needed. (Blouch, 1990; Macdonald, 1993; Smite, 1982)

  • Positive Impacts
  • food

Economic Importance for Humans: Negative

There are no know adverse affects that S. celebensis has on human economies. It might be speculated, however, that in agricultural areas, these pigs might present a problem as crop pests.

Conservation Status

Sus celebensis is a common species, and is not listed by the IUCN. It is locally abundant, and cannot be regarded as seriously threatened throughout its range at the present time. Budiarso states that he recorded 2,317 pigs harvested in the regions of Northern Sulawesi during 12 months in 1990 to 1991, and found that females are more susceptible to these commercial hunting operations which may make heavily exploited populations vulnerable. With the expansion of human settlements , S. celebensis is threatened by a combination of habitat loss and genetic contamiantion and/or disease through increased contact with imported domestic pigs Sus scrofa. (Budiarso, 1991; Macdonald, 1993)

Other Comments

The distributioon of Celebes wild boars has been greatly increased by humans, because these pigs were introduced to Halmahera, Flores and Timor when they become part of the local menu. On Roti, they were bred as domestic animals, but probably as a hybrid with Asian pigs. On Moluccas, the Aru Islands, and New Guinea (where they are known as Papua Pigs), piglets of this species have been reported to have actually been raised by the native women on their own breast milk! These pigs live half-tame and half-wild, voluntarily returning to the settlement at night when they are signaled by different drum signals of various owners. (Huffman, 1999; Parker, 1990)

Contributors

Nancy Shefferly (editor), Animal Diversity Web.

Nicole Noel (author), University of Wisconsin-Stevens Point, Chris Yahnke (editor, instructor), University of Wisconsin-Stevens Point.

Glossary

Australian

Living in Australia, New Zealand, Tasmania, New Guinea and associated islands.

World Map

acoustic

uses sound to communicate

agricultural

living in landscapes dominated by human agriculture.

altricial

young are born in a relatively underdeveloped state; they are unable to feed or care for themselves or locomote independently for a period of time after birth/hatching. In birds, naked and helpless after hatching.

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

carrion

flesh of dead animals.

chemical

uses smells or other chemicals to communicate

crepuscular

active at dawn and dusk

cryptic

having markings, coloration, shapes, or other features that cause an animal to be camouflaged in its natural environment; being difficult to see or otherwise detect.

diurnal
  1. active during the day, 2. lasting for one day.
endothermic

animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.

fertilization

union of egg and spermatozoan

food

A substance that provides both nutrients and energy to a living thing.

forest

forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.

introduced

referring to animal species that have been transported to and established populations in regions outside of their natural range, usually through human action.

island endemic

animals that live only on an island or set of islands.

iteroparous

offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).

motile

having the capacity to move from one place to another.

native range

the area in which the animal is naturally found, the region in which it is endemic.

omnivore

an animal that mainly eats all kinds of things, including plants and animals

oriental

found in the oriental region of the world. In other words, India and southeast Asia.

World Map

polygynous

having more than one female as a mate at one time

rainforest

rainforests, both temperate and tropical, are dominated by trees often forming a closed canopy with little light reaching the ground. Epiphytes and climbing plants are also abundant. Precipitation is typically not limiting, but may be somewhat seasonal.

sedentary

remains in the same area

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

sexual ornamentation

one of the sexes (usually males) has special physical structures used in courting the other sex or fighting the same sex. For example: antlers, elongated tails, special spurs.

social

associates with others of its species; forms social groups.

soil aeration

digs and breaks up soil so air and water can get in

swamp

a wetland area that may be permanently or intermittently covered in water, often dominated by woody vegetation.

tactile

uses touch to communicate

terrestrial

Living on the ground.

tropical

the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.

tropical savanna and grassland

A terrestrial biome. Savannas are grasslands with scattered individual trees that do not form a closed canopy. Extensive savannas are found in parts of subtropical and tropical Africa and South America, and in Australia.

savanna

A grassland with scattered trees or scattered clumps of trees, a type of community intermediate between grassland and forest. See also Tropical savanna and grassland biome.

temperate grassland

A terrestrial biome found in temperate latitudes (>23.5° N or S latitude). Vegetation is made up mostly of grasses, the height and species diversity of which depend largely on the amount of moisture available. Fire and grazing are important in the long-term maintenance of grasslands.

visual

uses sight to communicate

viviparous

reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.

year-round breeding

breeding takes place throughout the year

References

Blouch, R. 1990. Report from the Field: Indonesia. Smithsonian Institute Conservation and Restoration Centre Newsletter, 1: 6-8.

Budiarso, W. 1991. The importance of Sulawesi wild pig *Sus celebensis* as a source of meat in North Sulawesi.. Universitas Sam Patulangi and World Wild Fund for Nature Indonesia Program: 19.

Hooijer, D. 1969. Pleistocene Vertebrates from Celebes, *Sus celebensis*. Muller & Schlegel,1845. Beaufortia, 16: 215-218.

Huffman, B. 1999. "Celebes Pig: Sulawesi Warty Pig Sus celebensis " (On-line). Ultimate Ungulate Page. Accessed May 28, 2004 at http://www.ultimateungulate.com/Artiodactyla/Sus_celebensis.html.

Macdonald, A. 1993. Pig, Peccaries and Hippos. IUCN, 5.7: 155-160.

National Research Council, 1983. Little-known Asian Animals with a Promising Economic Future. National Academy Press: 75-79.

Nowak, R. 1999. Walker's Mammals of the World, Sixth Edition. Baltimore and London: The Johns Hopkins University Press.

Parker, S. 1990. *Sus Celebensis*. Pp. 20,21,33-47 in Grzimek's Encyclopedia of Mammals, Vol. 5. New York:

Smite, F. 1982. Threats to the Spice Islands. Oryx, 16: 323-328.

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