Welcome to yet another article in the (outstandingly successful, yet recycled from ver 1) series on babirusas. Observant readers will have noticed that, strangely, I’ve refrained thus far from using a scientific binomial for babirusas, plus I’ve consistently (I think) referred to them in the plural, and not as a single species. What gives?
Well, the proverbial cat is already out of the bag, but the traditional taxonomy where all babirusas are referred to the single species Babyrousa babyrussa is now defunct and there are good reasons for recognising several species. Babirusa taxonomy was reviewed by Groves (1980) who recognised four subspecies, one of which (B. babyrussa bolabatuensis from south-eastern Sulawesi) was named for Holocene fossils and is apparently extinct. A fifth subspecies, B. babyrussa beruensis, is larger than the more recent forms and known only from Pleistocene fossils.
In more recent publications, however (Groves 2001, Meijaard & Groves 2002a, b), it has been argued that most of the supposed subspecies are distinct enough to be recognised as distinct species, being as different from one another as are universally recognised species within other artiodactyl groups [adjacent head shot from Babirusa.Org]. Whether taxa are awarded subspecific or specific rank is of course subjective, but not only is it (arguably) misleading to include all of these taxa within a single species, there is also the practical problem that species are always regarded as more deserving of conservation effort than subspecies. If this is news to you, or seems odd or just stupid, here is what William Oliver recently had to say about the subject…
I am not really sure why, but species are generally regarded as being somehow more important than subspecies and, hence, merit higher conservation priority. I confess I can’t swallow this view without a good deal of choking and spluttering – particularly if one considers that a polytypic species – being an abstracted sum of its parts – doesn’t actually exist. In fact, the adoption of this view can be (and often is) positively unhelpful, in that subspecies are all too often ignored and species’ conservation priorities are thus ‘loaded’ in favour of the least threatened subspecies or populations – a patently ridiculous (and arguably irresponsible) situation’ (Oliver 2001, p. 4).
Whether there are political reasons for raising ‘subspecies’ to specific status or not, it is still clear that the named babirusa taxa are quite distinct from one another. The species are…
— B. babyrussa Linnaeus, 1758: a small species, with long, thick body hair and a well developed tail tuft. The common names Golden babirusa and Hairy babirusa have been used lately for this species. The upper canines of males are short and slender and cross the lower canines in lateral view. The upper canines tend to diverge or be subparallel, but they may be weakly convergent. B. babyrussa is from the Sula Islands (east of central Sulawesi) and Buru (just south-east of the Sula Islands). Most workers think that the babirusas were introduced to these islands, and if this is so we don’t know what their true place of origin was. Unfortunately babirusas from the adjacent eastern and south-eastern parts of Sulawesi remain unknown, so it is not possible to test whether or not they are particularly similar to B. babyrussa.
— B. togeanensis Sody, 1949: the largest species, it has sparser, shorter body than B. babyrussa and, in contrast to B. celebensis, the tail tuft is well developed. The upper canines of males are this species’ most distinctive feature: they are short, slender, rotated forwards and always converge. It is endemic to the Togian (or Togean) Islands, an island group that has been separated from the adjacent eastern arm of Sulawesi for c. 12,000 years. This suggests that the babirusas from the eastern arm of Sulawesi should be closest related to the Togian animals, but an absence of specimens makes this impossible to test (Meijaard & Groves 2002b). It cannot be ruled out that Togian babirusas were introduced to the Togian Islands by people. A male Togian babirusa is shown here.
— B. celebensis Deninger, 1909: this is the babirusa we are all familiar with. It has sparse or absent body hair, a nearly hairless tail tuft, and long, relatively thick upper canines that emerge vertically, converge slightly and curl dorsally in a circle. B. celebensis is the commonest babirusa, the only one for which widely available photos are available, and the only species kept in captivity [it is claimed here and there that B. babyrussa is kept in captivity and that there are no B. celebensis specimens outside the US. I think this is incorrect and that people have wrongly assumed that many captive B. celebensis individuals represent B. babyrussa. Let me know if you know better]. B. celebensis is only definitely known from the northern arm of Sulawesi [map below from Meijaard & Groves 2002a].
On mainland Sulawesi, babirusas are certainly not restricted to the northern arm: historically they occurred across the island, and those of central Sulawesi at least are still extant. Unfortunately their specific status remains uncertain as not enough data is known – while populations might be continuous with B. celebensis and hence referable to that species, a skull from near Kulawi in central Sulawesi differs from other babirusas in being particularly small, in having proportionally long lower premolars, and in various cranial proportions. Meijaard & Groves (2002b) thought that the skull had its strongest affinities with Togian babirusas, and they concluded that it probably represented another taxon. More data is needed to confirm this. A babirusa skull photographed on sale in south-central Sulawesi has also proved enigmatic, being quite different from the Kulawi skull and unidentifiable based on the data available (Meijaard 2003).
Babirusas are also known from southern Sulawesi. Wiles & Mustari (2002) reported a skull, a tooth, and some eyewitness accounts of live animals from south-east Sulawesi, but in south-west Sulawesi babiruas are extinct so far as we know (though this needs confirmation). Hooijer (1950) named B. bolabatuensis (though originally as a subspecies of B. babyrussa) for teeth from the south-western arm of Sulawesi, though it has most recently been concluded that the material from this region cannot be reliably identified taxonomically (Meijaard & Groves 2002b). The Kulawi skull has at times been suggested to represent a modern example of B. bolabatuensis.
What with the taxonomically indeterminate babirusas of central Sulawesi, the unconfirmed extinction of those of southern Sulawesi, and the rumoured presence of babirusas on various small islands around Sulawesi, they are a ripe area for discovery and further research. Reports, photos and specimens are badly needed from these regions, and we have some way to go before babirusa diversity and biogeography is properly understood. And, of course, the phylogenetic hypotheses encapsulated in the ‘new taxonomy’ used here are not the last word on the subject and have arisen due to application of a phylogenetic species concept that some workers find objectionable. More on this matter soon – and, indeed, yet more on babirusas soon to come…
For previous babirusa articles see…
- The deer-pig, the Raksasa, the only living anthracothere… welcome to the world of babirusas
- Are anthracotheres alive and well and living on Sulawesi? No, but it was a nice idea. Babirusas, part II
- What’s with the bizarre curving tusks? Babirusas, part III
- When babirusas fight (babirusas, part IV)
- This little piggy went ploughing (babirusas, part V)
For other Tet Zoo articles on artiodactyls see…
- McGowan’s mystery bovid
- The legend of Hogzilla
- Welcome…. to the world of sheep
- Return…. to the world of sheep
- Tet Zoo picture of the day # 23 [on entelodonts]
- Deer oh deer, this joke gets worse every time I use it
- Duiker, rhymes with biker
- Sable antelopes and the miseducation of youth
- Giant killer pigs from hell
- The plasticity of deer
- Over 400 new mammal species have been named since 1993
- Great Asian cattle
- Stuffed megamammal week, day 1: Khama
- Stuffed megamammal week, day 2: Eland
- Stuffed megamammal week, day 3: Okapi
- Death by lightning for giraffes, elephants, sheep and cows
- Dromomerycids: discuss
Refs – –
Groves, C. P. 1980. Notes on the systematics of Babyrousa (Artiodactyla, Suidae). Zoologische Mededelingen 55, 29-46.
– . 2001. Mammals in Sulawesi: where did they come from and when, and what happened to them when they got there? In Metcalfe, I., Smith, J. M. B., Morwood, M. & Davidson, I. (eds) Faunal and Floral Migration and Evolution in SE Asia-Australia. A. A. Balkema Publishers (Lisse, The Netherlands), pp. 333-342.
Hooijer, D. A. 1950. Man and other mammals from Toalian sites in south-western Celebes. Verhandelingen der Koninklijke Nederlandsche Akademie van Wetenschappen, Afd. Natuurkunde Tweede sectie 46, 7-164.
Meijaard, E. 2003. Note on a photo of two babirusa skulls from Rante-pao, south-central Sulawesi. Asian Wild Pig News 3 (1),12.
– . & Groves, C. 2002a. Proposal for taxonomic changes within the genus Babyrousa. Asian Wild Pig News 2 (1), 9-10.
– . & Groves, C. 2002b. Upgrading three subspecies of babirusa (Babyrousa sp.) to full species level. Asian Wild Pig News 2 (2), 33-39.
Wiles, R. & Mustari, I. A. H. 2002. Records of babirusa and warty pigs in SE Sulawesi. Asian Wild Pig News 2 (2), 31-32.