Captive Anoa, Port Lympne, UK, 2013 (Aspinall Foundation)

Lowland anoa
(Bubalus depressicornis)
Mountain anoa
(Bubalus quarlesi)

Other names: Dwarf Buffalo

(Note: If not otherwise stated, information is applicable to both anoa species)

Status

Both species are Endangered.
Current taxonomy of the 2 recognised species of anoa is differentiated by the different altitudes they are found (see below). However, recent genetic results have shown that the population structure is in fact differentiated into the biogeographic areas of Sulawesi and Buton Island, into 4 subpopulations. Therefore, the current taxonomy will be reorganised in the near future, as the genetic data shows the real population structure and therefore the taxonomic status (Burton, pers. comm.).

Population estimate

Estimating population sizes has proven difficult due to the complication of identifying the range of the two anoa species and also as an island-wide population survey as yet to be completed. However, reports have shown they still have a relatively wide distribution within Sulawesi, which consists of approximately 2,500 mature individuals, although their range is increasingly fragmented and it is believed that no subpopulation consist of more than 250 mature individuals.2 The rate of population decline is thought to be 20% over two generations.2

Distribution and habitat preference

Both anoa species are endemic to Indonesia and are believed to be exclusively found on Sulawesi and Buton Island off the southeast coast.2 It is currently unknown if the two recognized species; Lowland (Bubalus depressicornis) and mountain anoa (Bubalus quarlesi), are sympatric and thus occur in the same geographical area, or are parapatric and so although occur in areas close by their ranges do not actually overlap. As yet, local distribution of both anoa species remains unclear.2

Fig.1. Lowland Anoa Click map for larger view. Click anywhere to return.

Because work is ongoing to determine the relationship between genetic and previously published taxonomic information, both are highlighted below. Therefore, in determining priority conservation areas, genetic variation of anoa known to have at least four sub-populations (Burton et al., In press), as well as the differences in altitude (below 1,000 m asl and above 1,000 m asl) in the forest area region has become the basis in determining the conservation strategy of anoa.

Lowland anoa: This species is typically found up to 1,000 m.8 It is proposed (from skull records and morphological descriptions) that lowland anoas are present in the northern peninsular, as far east as the Bogani Nani-Wartabone National Park, across the central region and ranging to the tip of the eastern and southeastern peninsulars as well as north and central Buton Island.2 The assumed current range of the lowland species can be seen in figure 1.

They are generally found in both primary and secondary lowland, swamp and mangrove forest regions, and have previously been reported to inhabit areas along the coast as well as high mountainous areas.6,9

Fig. 2. Mountain Anoa Click map for larger view. Click anywhere to return.

Mountain anoa: Unlike the lowland anoa, the mountain species are generally recorded from 1,000 to 2,300 m, as well as near sea level.7,10 Again, using skull records and morphological descriptions, it was ascertained that mountain anoas were present across most of the Central region of Sulawesi and north of Buton Island.2 However, confirmation of additional range could not be obtained, although some reports have suggested that this species can also be found in the north peninsular and along some of the southeastern peninsular.4 Establishing mountain anoa populations alone can be challenging due to the difficulty in differentiating mountain anoa from young lowland anoa.8

This species is usually found in dense forest and habitats with dense understory vegetation and in areas with plentiful water sources and low human activity.3,10