| Lowland Anoa | |
|---|---|
 | |
| Scientific Classification | |
| Kingdom | Animalia |
| Phylum | Chordata |
| Class | Mammalia |
| Order | Artiodactyla |
| Family | Bovidae |
| Genus | Bubalus |
| Species | B.depressicornis |
| Conservation Status | |
 Endangered | |
The lowland anoa (Bubalus depressicornis) is a small Bovid in the Artiodactyla order, also known as anoa de Ilanura or anoa des plaines, in the Anoa subgenus from the genus Bubalus.
Taxonomy[]
The taxonomic classification of the anoa is controversial (Groves, 1969), and although debate continues over the existence of two species of anoa, evidence using cytochrome B gene haplotypes suggests the two lines are distinct species (Schreiber et al., 1999). These two species have been placed in the distinct genus Anoa in the past (e.g., Hooijer, 1948), but both morphological and genetic reassessments tend to support its inclusion as a subgenus inside the Bubalus genus, with Bubalus arnee (Groves, 1969; Tanaka et al., 1996). However, further analyses are required to clarify their phylogenetic relationships (Kikkawa et al., 1997; Pitra et al., 1997).
Distribution[]
The lowland anoa is endemic to the Indonesian island of Sulawesi (Celebes) and peripheral islands in Indonesia. The total range occupied by this species is approximately 3,000km2 (Hedges, 2000). The island of Buton in the Southeast of Sulawesi is also one of the last remaining strongholds for the lowland anoa. No conclusive theory allows explanation of the coexistence of two similar species of anoas in Sulawesi, and it is still unclear if they currently live sympatrically or if they are separated by an altitudinal or other type of segregation (Burton et al., 2005).
Description[]
Total height at the shoulders is about 95 to 110 cm and body mass 200 to 300 kg. The limbs are short and the body is stocky (Rabor, 1977). Neonates are reddish-brown with dark brown legs and a black dorsal line. Calves a few months old have light brown bodies which later turn dark brown or slate colored. The developpement of a slate-colored pelage occur at 3 to 4 years old in males and females. In most individuals the slate-colored pelage darkens to black, but some adult females can be rather brown or brown-tinged. Change in haircoat color and shape of the horns can be used in the estimation of the age of tamaraws (Kuehn, 1986). White markings are present above the hooves as well as on the inner lower forelegs, similar to the lowland anoa (Bubalus depressicornis). White markings are also present on the inside of the ears (Custodio et al., 1996). Adults present short horns (35-50 cm long), which grow upward and are triangular on cross section. Sexual dimorphism is low, the male presents a thicker neck than the female.
Lifespan[]
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Ecology[]
Little is known about the ecology of the lowland anoa due to its elusive behaviour. The largest animal species of Sulawesi lives in lowland old growth forests, and seems to favour swampy areas within forests along the coast, including mangroves (Melisch, 1995). This browser species is supposed to play an important role in contributing to the dispersion of numerous seeds. Food intake includes seeds of Lithocarpus spp., Castanopsis sp. and Leptospermum spp. Ficus spp. Eugenia spp., Palaquium spp., Antidesma spp., young banana trees, bamboo shoots and rattan sprouts are also favoured. Anoa has been reported drinking seawater (Whitten et al., 1987). Adult lowland anoa apparently live singly or in pairs, rather than herds (Dolan, 1965). The lowland anoas are particularly unsociable in captivity and they can be very aggressive toward humans especially during pregnancy; several accounts of this species of anoa attacking humans with its sharp horns have been recorded. The horn-scouring tress and the soil-scratching by adult male after defecation seems to be an expression of their territorial behaviour (Mustari, 1995). They seem to be more active during the night, while staying hidden in dense vegetation at daytime, but such an activity rhythm could be the result of repeated human disturbances. The lowland anoa appreciates wallowing in mud. Estimates of population densities range from 1.1 to 1.3 individuals/km2 (Burton et al., 2005). Sexual maturity occurs after 2 or 3 years. A single calf is born after 9 to 10 months of gestation. It is unclear whether reproduction is seasonal in the wild, but lowland anoas reproduce throughout the year in captivity. Longevity in captivity is 20-30 years. Native predators of lowland anoa include the reticulated python (Python reticulatus).
Conservation[]
This species is threatened by poaching, forest habitat destruction for timber collection and agriculture, and possibly infectious diseases transmission from domestic cattle. The lowland anoa is mainly poached for its meat used for local consumption. Many anoas are also thought to get caught accidentally in traps laid for wild pigs, including inside protected areas (e.g., in the Lambu Sango Nature Reserve on the island of Buton). This extremely shy species is very sensitive to human disturbance (hunting, timber extraction, rattan exploitation, etc). Wild population size is estimated between 3,000 and 5,000 individuals, but is in rapid decline. The population of anoas in Tangkoko-Dua Saudara Nature Reserve (8,745ha) has experienced a decline of 90% between 1978 and 1994 (O’Brien and Kinnaird, 1996) and is now extirpated (Burton et al., 2005). Important populations still exist in the more remote parts of Sulawesi where the poaching pressure is lower (e.g., Lore Lindu National Park, Bogani Nani-Wartabone National Park, and Tanjung Peropa Nature Reserve). However, the continued economic crisis in Sulawesi, compounded by recent regional development setting and obsession to gain local revenue from excessive natural resource extraction has put pressure on the current and future conservation of remaining forests. Nearly all the lowland forests of Sulawesi have already disappeared. The timber business is lucrative and has therefore involved politicians, government officials and other regulatory stakeholders. Due to its hilly topography, Buton Island still has a considerable amount of forest cover but it has been severely damaged and continues to be threatened. Moreover, despite the small size of Buton Island and its poor soil fertility, this area is still a transmigration area destination. Unfortunately, all the transmigration areas have mostly been developed at the expense of Lambu Sango Nature Reserve, seriously affecting the habitat of the anoa. The lowland anoa is listed in Appendix I of the CITES. Ex situ conservation programs are implemented for lowland anoa in US, Europe and Asia but the difficulties to assign captive individual to appropriate taxa seriously complicate the management of this captive population. There was a twofold increase in ten years to reach a total of 125 animals recorded in the species’ studbook in December 1998. However, several individuals are suspected to result from hybridization with Bubalus quarlesi (Nötzold, 1999). The largest captive group of this species occurs in the Peace River Center for Conservation of Tropical Ungulates in Arcadia, Florida.
