Another article on babirusas – yaay! Like many (but not all) pigs, babirusas are omnivorous, and are said to eat invertebrates whenever they find them. They have also been reported to eat fish on occasion, to catch small mammals, and even to catch and eat the juveniles of other babirusas (Leus & Morgan 1995). They eat all kinds of plant material, including fruits, leaves, flowers, berries, nuts, bark and tubers, and they not only browse and dig to obtain such items, they are also surprisingly good at standing bipedally (without support) to feed on leaves. This again is a curious parallel with deer, in particular Sambar.
So… what’s with the bizarre curving tusks? Present only in males (females lack canines entirely), they grow continuously throughout life, and their growth, anatomy and function are all odd. The lower canine is normal in position and anatomy, it’s just that it becomes particularly long during growth, overlapping the outside edge of the snout as it grows. The upper canine is another story. Initially growing downwards – like any normal mammalian upper canine – it is then rotated as the alveolus itself turns to force the tooth upwards, and it eventually emerges from the dorsal surface of the snout. The most anterior part of the spiral parallels the long lower canines. As mentioned earlier, we’re mostly familiar with those babirusas where the upper canines curl in a circle as they grow, forming a spiral over the animal’s forehead. As we’ll see later, spiralling upper canines of this sort are not present in all kinds of babirusas.
Regardless, in those babirusas with spiralling tusks, some authors say that, if the animal lives long enough, the tusks grow fatally into the face (Irven 1996). However, in the old male skulls that I’ve seen (see accompanying images: the woodcut is from Alfred Russel Wallace’s 1869 The Malay Archipelago), the tips of the upper canines begin the anterodorsal part of their curvature a short distance dorsal to the upper surface of the skull, so if they were to continue to grow they would harmlessly curl upwards. Furthermore, so far as I can tell from the literature, no-one has ever found a babirusa skull in which the upper canines have bored into the bone [though a colleague told me that he once saw a specimen where exactly this had happened... ].
A Balinese demon with curling tusks that emerge from its cheeks – the Raksasa – might have been inspired by stories or sightings of babirusas (Groves 1980) (Raksasa rendition below from here].
Famously, people on Celebes once supposed that babirusas hung from trees with their tusks, and then stayed there in wait for passing females. This seems to be the one ‘fact’ about babirusas that everyone knows, as it’s mentioned in just about every article, paper and book that discusses them. It’s often stated that the tusks might be used in display or fighting, but there’s also the old idea that the tusks allow males to push their way through dense stands of ratten cane, thereby allowing tusk-less females and juveniles to follow in single file behind. Well, maybe the tusks can be used in this way, but this can’t of course have been the main selection pressure driving the evolution of the teeth, given that the intermediate stages leading up to this ‘end’ condition wouldn’t have been at all useful. More on tusks in the next post.
Perhaps surprisingly in view of their sensitivity to cold, babirusas have fared quite well in zoological collections, having first been kept in Europe at ‘la Ménagerie du Roi’ in Paris during the 1840s, and having bred at London Zoological Garden as early as 1884. In 1995, 29 zoos worldwide held babirusas. Several individuals have survived in captivity for more than 20 years, with the record holder being an animal kept at Chicago which, on its death in 1920, was 21 years and 4 months old. Paul Irven (1996) wrote that captive babirusas are ‘sensitive and responsive … with an endearing character’. They are also said to exhibit excitement and enthusiasm on greeting familiar people, engaging in tail wagging, head shaking and jumping and running about. This friendly disposition makes them quite different from many other non-domesticated suids.
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
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.
Irven, P. 1996. The Babirusa. Mainly About Animals 29, 5-7.
Leus, K. & Morgan, C. A. 1995. Analyses of diets fed to babirusa (Babyrousa babyrussa) in captivity with respect to their nutritional requirements. Ibex J.M.E. 3, 41-44.