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Banteng
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The Banteng, Bos javanicus is an ox that is found in Burma, Thailand, Cambodia, Laos, Vietnam, Borneo, Java, and Bali. Some Banteng were introduced to Northern Australia during British colonization in 1849 where they are doing extremely well having grown in number spurred by the trophy hunting incentive.
Banteng have been domesticated in several places in Southeast Asia, and there are around 1.5 million domestic Banteng, which are called Bali cattle. These animals are used as a working beast, and for their meat. Domestic and wild Banteng can mate and offspring are often fertile. Domesticated bantengs have been introduced in 1849 to northern Australia and form a feral population there.
DistributionAs of February 2005, the Banteng population of the Cobourg Peninsula is 10,000 head, making the population in the Northern Territory the largest herd in the world. Before the study by Charles Darwin University it was believed that only 5,000 pure-strain Banteng survived worldwide. In their native range the largest herd numbers less than 500 head.
BehaviourBanteng live in sparse forest where they feed on grasses, bamboo, fruit, leaves and young branches. The Banteng is generally active both at night and day time but in places where humans are common they adopt a nocturnal schedule. Banteng tend to gather in herds of two to thirty members.
Subspecies - Java Banteng (B. j. javanicus): Java; Males are black, females buff.
- Borneo Banteng (B. j. lowi): Borneo; Smaller then Java Banteng and the horns are steeper, bulls are chocolate-brown.
- Burma Banteng (B. j. birmanicus): Burma, Thailand, Cambodia, Vietnam; Males and females are usually buff, but in Cambodia are 20 % of the bulls blackish, and on the Malayan Peninsula in Thailand are even most of the bulls black. These subspecies is classified as Critically Endangered by the IUCN.
CloningThe Banteng is the second endangered species to be successfully cloned, and the first to survive for more than a week (the first was a Gaur that died two days after being born). Scientists at Advanced Cell Technology in Worcester, MA, USA extracted DNA from Banteng cells kept in the San Diego Zoo's "Frozen Zoo" facility, and transferred it into eggs from domestic cattle, a process called somatic cell nuclear transfer. 30 embryos were created, sent to Trans Ova Genetics, which implanted the fertilized eggs in domestic cattle. Two were carried to term and delivered by caesarian section. The first was born on April 1, 2003, and the second two days later. The second was euthanized, but the first survived and, as of September 2006, remains in good health at the San Diego Zoo.
The Banteng in Australia Overview of Australian Presence: The domesticated form of the banteng was first introduced to Australia in 1849 with the establishment of a British military outpost on the Cobourg Peninsula called Port Essington. In all 20 animals were taken to the Western Arnhem Land, a part of current day Northern Territory, as a source of meat. Only a year after the outpost’s establishment, poor conditions such as crop failure and tropical disease lead to its abandonment. With the departure of British troops, the banteng were released from their grazing pastures and allowed to form a feral population. By the 1960’s, researchers realized that a population of about 1500 individuals had developed in the tropical forests of the Cobourg Peninsula.
Since their introduction in 1849, the population has not strayed far from its initial point of domesticated life; all currently live within the Garig Gunak Barlu National Park. As of 2007, the initial population had grown from only 20 in 1849 to 8,000-10,000 and is used exclusively for sport hunting and aboriginal subsistence hunters.
Physiology and Reproduction in Australian Banteng Populations The Banteng of the Cobourg Peninsula have developed slightly different life processes than their domesticated counterparts. Growth over lifetime is sexually dimorphic; males grow faster and are larger than females. Furthermore, females reach maximum body mass in three to four years, while males take five to six. Sexual maturity occurs three to four years, and two to four years in males and females respectively. Fecundity also declines in older females. Breeding is seasonal, with maximum mating occurring during the months of October and November, and most births take place in the winter months of June to August. Calf mortality is high in the first six months of life, and declines quickly thereafter with increasing body size. When compared to domestic populations, it was found that increased food in captive conditions allowed respectively higher fecundity, earlier maturation, and lower juvenile mortality.
Australian Environmental Impact: Despite being an non-native species, the feral australian banteng, has adapted to positively interact with native avian populations. Studies have shown that mutual relationships have developed involving the removal of ectoparasites residing on the bovid body by the Torresian crow (Corvus orru). This is especially notable because it is the first-known relationship of such a kind, which only needed 150 years to develop, where a native bird relies on a non-native wild mammal.
Within the Garig Gunak Barlu National Park, where practically all Banteng reside, there has been limited damage due to overgrazing. They are primarily found within the monsoon forests, but cause little damage, especially when compared to feral pigs. Within the forest, densities were found to be around 70 per square kilometer, and have remained near their initial introduction point 140 years ago because of the possibility that their habitat is a uniquely suitable mosaic of grassland and monsoon forest. Another likely reason for their limit dispersal is the presence of fences along the southern end of the peninsula installed to manage movement of other feral species like the water buffalo. Interaction with the habitat is also unclear in another aspect involving monsoonal forest succession into grasslands. Within the Garig Gunak Barlu National Park researchers noticed that monsoonal seedling were encroaching into previously well established grasslands. It is thought that the grazing by banteng limits potential fuel for grassland fires to take back monsoonal forest and spreads monsoonal seeds, but was still unclear after the study.
Conservation Value of Australian banteng population for Bos javnicus Since Australian banteng are considered an invasive non-native species, some environmental scientists believe that a complete removal of the limited population will allow previously occupied habitat to regress back to its pre-1849 state and allow native species to return. However, this thought of return to pristine conditions is not clearly favorable because of the socio-economic niche it has formed, as well as playing an integral role in helping to recover endangered wild individuals in Asia.
Small populations in northern Australian are heavily relied on as a source of income for sport hunting as well as aboriginal peoples. Studies revealed that as much as AU$200,000 can be made annually on hunting without damaging populace stability.
The current population of banteng in Australia has become the center of debate due to the endangered status it has achieved in its native Asia. Wild bantengs are incredibly rare in Asia due to loss of suitable habitat, even though they are regularly used in domestic agricultural settings by as grazers. But these domestic bantengs of South East Asia have varying degrees of introgression from other domesticated Bos species. The Australian bantengs are derived from the domesticated form and not from the rare wild form. However, genetic studies have revealed that the Australian bantengs are identical to the Asian Bos javanicus and are therefore not crossed with other species, what places the Australian population in a different conservation category relative to its domesticated conspecific in South East Asia.
Since a small founder event occurred with only approximately 20 previously domesticated individuals, a genetic bottlenecking has inevitably occurred, causing all current individuals in Australia to be genetically similar and lacking genetic diversity due to generational inbreeding. This was proven using microsatellites, 12 in all, were used to determine that their inbreeding coefficient was high, F=0.58. These findings were comparatively much higher than the endangered artiodactyl populations in Southeast Asia. Despite the limited genetic pool of this population, conservationists are hopeful that preservation of at risk populations can transpire. Some have proposed a deliberate introduction of the endangered populations to the stable but non-native Australian variety will enable viable conservation, even though it is not entirely known how it will affect Northern territory grazing ranges.
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