The bearded pigs

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ResearchBlogging.org

One of the most remarkable pigs has to be the Bornean bearded pig Sus barbatus, one of two currently recognised bearded pig species. The other is the much smaller, shorter-faced Palawan bearded pig S. ahoenobarbus of the Philippines: genetic work suggests that S. ahoenobarbus is not a close relative of S. barbatus, but actually closer to the Celebes warty pig S. celebensis and other Philippines pigs (Lucchini et al. 2005). S. barbatus occurs on Sumatra, Bangka, the Riau archipelago and the Malay Peninsula as well as Borneo. There are two subspecies: S. b. barbatus has long cheek beards while S. b. oi has more wiry-looking snout hair. Molecular work confuses the distinction between these two forms, since Sumatran populations supposed to belong to S. b. oi are actually closer to the nominate Bornean population that to Malaysian populations of S. b. oi (Lucchini et al. 2005, p. 33).

One hypothesis for the evolution of Sus proposes that the bearded pigs and the Java warty pig S. verrucosus are the sister-group to a clade that includes the Wild boar S. scrofa and Celebes warty pig S. celebensis. Supposedly, members of the bearded pig lineage can be distinguished from members of the wild boar lineage by their especially elongate snout and 'saw-edged' fronto-nasal suture (Groves 1983, 1997). Conspicuous differences in size between the bearded pig populations of Sumatra, Borneo and elsewhere meant that particularly big individuals collected on Borneo were initially thought to represent an additional species; S. gargantua Miller, 1906.

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Comparatively little is known about the ecology and behaviour of bearded pigs. They're reportedly migratory across part of their range, moving back and forth between areas during the year, and sometimes gathering in huge herds of hundreds of animals (Groves 1981). I'd like to know more about what they do with all that crazy snout hair, but this subject doesn't seem to have been much explored in the literature. It seems to be sexually dimorphic, with males having hairier snouts and cheeks.

These photos were taken at Berlin Zoo by Markus Bühler. Berlin Zoo includes quite a few neat bits of signage and artwork: the sign below does a nice job of illustrating some of the diversity present in the wild pigs of south-east Asia. As you can see, this diversity is pretty impressive. The taxonomy of these pigs has been much discussed and debated and how many of the various forms are regarded as 'subspecies' or 'species' remains the topic of disagreement (see Groves 1997, 2001). It's an important issue, since many of these pigs are threatened and of great conservation interest.

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For previous Tet Zoo articles on pigs, see...

Ref - -

Groves, C. P. 1981. Ancestors for the Pigs: Taxonomy and Phylogeny of the Genus Sus. Technical Bulletin 3, Department of Prehistory, Research School of Pacific Studies, Australian National University, pp. 96.

- . 1983. Pigs east of the Wallace Line. Journal de la Société des Océanistes 77, 105-119.

- . 1997. Taxonomy of wild pigs (Sus) of the Philippines. Zoological Journal of the Linnean Society 120, 163-191.

- . 2001. Taxonomy of wild pigs of southeast Asia. Asian Wild Pigs News 1 (1), 3-4.

Lucchini, V., Meijaard, E., Diong, C. H., Groves, C. P., & Randi, E. 2005.Journal of Zoology, 266, 25-35

Lucchini, V., Meijaard, E., Diong, C. H., Groves, C. P. & Randi, E. 2005. New phylogenetic perspectives among species of South-east Asian wild pig (Sus sp.) based on mtDNA sequences and morphometric data. Journal of Zoology 266, 25-35. [Have added the same ref twice as cannot get research blogging to behave itself.]

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I didn't even know that bearded pigs exist. They look positively amusing, not even being able to see their own snouts properly. I'll definitely have to read the literature one day as pigs and their relatives absolutely fascinate me.

When I visited the Maliau Basin in Borneo, it was a thrill to see a bearded pig walk out of the forest towards us, as if expecting us to toss it some food. Bearded pigs are also among my favourite animals at the Singapore Zoo.

If I'm not wrong, the bearded pig (and many other Southeast Asian pig species) are threatened, not just by deforestation (which creates habitat more favorable to wild boar), but also hybridisation with wild boar (often non-native, like in Borneo, Philippines & Sulawesi) and domestic pigs.

It's too unfortunate that Indonesia has no fossil site before Quaternary, because Tertiary Indonesian faunas were pivotal for understanding evolution of Eurasian faunas: almost nothing is known about origin of Suini, SE Asian viverrids, gibbons, tupaias, etc.

By J. S. Lopes (not verified) on 19 Jun 2011 #permalink

Darren:

S. b. oi

Was it named by some Cockney scientist?

During the Pleistocene all those western Indonesian islands would have been connected to each other and mainland South-East Asia. Is it known if all those species of pig used to coexist, at least in the now submerged lowlands? I guess some diversity would be Holocene in origin, but surely that doesn't apply to all of it?

Unscientific, but my first reaction was "Wow!".

That is an amazing animal!

A quick check on ISIS lists zoos holding them as follows:

London 3.6.0
Munich 1.1.0
Lowry 0.2.0
San Diego 6.9.1
Philadelphia 1.0
Taiping 3.3.0
Singapore 18.19.1
Taipei 1.1.0
Kuala Lumpur 12

Hope this helps anyone wanting to see one

I'm curious too about the purpose for all that hair... Many species of orchids employ elaborate fringes like that to increase the surface area for dispersing subtle odors, some of which may imitate pheromones. (Dendrobium henryanum is one example subtle musty odor that might mimic a pheromone... and Rhyncholaelia digbyana is another with powerful moth-attracting odor at night.)

If this is a sexually dimorphic characteristic, maybe it has to do with releasing odors for some sort of communication... do pigs have scent glands on their faces? Or maybe it simply allows the pigs to trap scents for a little longer to analyze them. That brushy beard would certainly collect odors.

By Scott Portman (not verified) on 20 Jun 2011 #permalink

Alan:

A quick check on ISIS lists zoos holding them

Berlin Zoo (where Markus Bühler's photos were taken) seems to be missing from that list.

Wow! What marvellous creatures! I'm tempted to ask if they inspired some of the more elaborate victorian whisker styles (like Austro-Hungarian Emperor Franz-Josef) but I suppose not.
Whiskers as a means of dispersing scent is an interesting idea. On the other hand, they're so visually striking.

By John McConnaughy (not verified) on 22 Jun 2011 #permalink

I had the privilege of seeing a bearded pig at London Zoo. It was such a character, running rings around his enclosure and investigating the anoa on the other side of his enclosure gate. The keepers had given him dead branches to play with since he seemed to like shaking them around and hearing them rattle. An experience I'll never forget!
Thanks for including them on tetzoo.