15 The Babirusa

The babirusa (Babyrousa babyrussa) is a piglike animal whose closest relative appears to be an ancestral animal that lived in Europe 35 million years ago. It is easily tamed, and in its native area there is an ancient tradition of raising young babirusa for meat and for the males' unique tusks. The animal appears to reproduce well in captivity, and with good management techniques it might gain wide use in the tropics.

Appearance and Size

Male babirusa can be up to 110 cm long and 80 cm tall and weigh up to 100 kg; females are smaller. The male has large upper canines that grow upwards, piercing right through the flesh of the snout and curving back and downwards towards the forehead without ever entering the mouth. The female may sometimes have small upper canines projecting through the skin of the upper lip.

The animal is more slender than a pig of similar size. It has a gray or brown-grey skin color, although one subspecies, Babyrousa babyrussa babyrussa, has light body hair that is fawn colored or black.

Distribution

The babirusa is unique to a few islands of eastern Indonesia: north, central, and southeast Sulawesi, the Togian Islands, and the Sula (Taliabu and Sulabesi) and Buru Islands. On Sula and Buru it is probably not native but was introduced in prehistoric times.

Status

On Sulawesi the babirusa remains abundant, despite hunting and the widespread clearing of the forest. Nevertheless, disturbances created by wood and rattan collectors, hunters, loggers, and farmers threaten the babirusa's survival. Throughout the rest of its range, it is also vulnerable to extinction.

Biologists are particularly concerned about some of the babirusa subspecies. The one from the north of mainland Sulawesi, Babyrousa babyrussa celebensis, is still relatively abundant in places and is probably in no immediate danger. The Togian Islands' subspecies, Babyrousa babyrussa togeanensis, is abundant in small islands but is threatened by Indonesia's settlement programs and deforestation. The Buru and Sula Islands subspecies, Babyrousa babyrussa babyrussa, may already be extinct; there have been no confirmed sightings in recent years.

In 1981, there were 26 male and 27 female babirusa held in six zoo collections; 22 of these animals are in the Surabaya Zoo in Indonesia, where they breed well. Most, if not all, are believed to belong to the mainland Sulawesi race.

Habitat and Environment

The animals mainly inhabit moist forests at low altitudes.

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Biology

Precise details of babirusa biology are unknown, but the stomach has an extra sac, suggesting that the animals may have some ability to break down cellulose. Indeed, they browse leaves, a behavior more often found in a deer than in a pig, and have been referred to as "ruminant pigs." Babirusa also live on roots, berries, and grubs, making them true omnivores. Compared to other pigs, they do little rooting, and in captivity their enclosures remain quite grassy.

Babirusa are said to be sexually mature at 5-10 months, but this depends on nutrition. Gestation length is about 158 days. One or two young are produced although there are some reports of litters of three.

One specimen was kept for 24 years in captivity.

 

Behavior

The babirusa is a social animal that moves in groups. A retiring native of the dense jungle, it is a fast runner and swims readily. Mating behavior in captivity generally resembles that of domestic pig. Evidence from zoo animals suggests that the male must be removed from the young at birth but that by the time they are a month old the young are safe from paternal attack.

Uses

When captured young or reared in captivity, the babirusa is easily tamed. It has potential as a domesticated species, and with appropriate management may provide a useful source of meat. The meat is tasty and of good quality.

Because of its unique tusks, the skull of the male finds ready markets. This could provide additional income to farmers raising babirusa for meat. The ivory of the tusks could also be a resource for local artisans.

Potential Advantages

As noted, the anatomy of the stomach suggests that the babirusa may be able to make more efficient use of fibrous foodstuffs than other pigs.

Limitations

The babirusa produces only one or two young after a gestation period of just over five months; it may therefore take considerable time to build up herds.

Although the babirusa is easily tamed, it is not known whether it can be husbanded in large groups. Also, present lack of knowledge of the animal's nutrition may restrict its husbandry.

Research and Conservation Needs

The number of animals in the wild is decreasing, and attempts should be made to determine their exact status. Particular attention should be paid to the subspecies Babyrousa babyrussa togeanensis and Babyrousa babyrussa babyrussa. Captive breeding programs for these subspecies should be started.

When seen in longitudinal section, the stomach of babirusa presents striking similarities to that of a relatively simple ruminant such as the domestic sheep. Every part except the omasum, even including a rudimentary reticulum, is represented and occupies the same relative position. The babirusa stomach differs from that of the domestic pig chiefly in the enormous size of the diverticulum ventriculi, the prominence of the constrictions that delimit its three main divisions, and in the size and complexity of the cardia. Regions corresponding to parts of the ruminant stomach are labeled in brackets. (Information from Davis, 1940; diagram courtesy Field Museum of Natural History, Chicago.)

Wild populations should be maintained in several regions to ensure that the species" genetic base is retained. Advantage could be taken of the large number of islands in eastern Indonesia to establish reserves for the different babirusa subspecies.

Currently, little is known about the biology of the animal in the wild— its diet, social behavior, or reproductive performance are almost unstudied. In view of the relatively small number of babirusa in zoos and the scarcity of information about the animal's growth rate and general biology, coordinated studies between zoos could provide much basic information. It has been suggested that a studbook be initiated for this species.

It is clear from chromosome analysis that this pig differs markedly in its karyotype from that of other pigs. However, more anatomical and biochemical knowledge is needed.

Basic parameters of the animal's reproductive physiology are not known. Questions to be answered include:

· Can the babirusa be induced to reproduce twice per year?

· Can babirusa embryos be developed to term in the uterus of the domestic pig? If so, can the number of babirusas be rapidly multiplied in this way?

· Does the babirusa genotypic and gestation-length difference with the common pig prevent the two from successfully crossbreeding? And if crossbreeding can be achieved, will the progeny be fertile?

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