Article

The rhinoceros of Borneo: a 19th century puzzle

From Munshipedia, the MBRAS digital historical encyclopedia

The rhinoceros of Borneo: a 19th century puzzle

L.C. Rookmaaker published this article in 1977 in the Journal of the Malaysian Branch of the Royal Asiatic Society (Vol. 50, No. 1, pp. 52–62), a volume dedicated to the memory of Tom Harrisson. The paper reconstructs the fifty-five-year taxonomic controversy over which rhinoceros species inhabited Borneo, demonstrating that the one-horned Javan rhinoceros (Rhinoceros sondaicus) was erroneously assigned to the island from the early 1860s until 1895, when the two-horned Sumatran rhinoceros (Dicerorhinus sumatrensis) was correctly identified as the sole species ever present there.

Summary

The article traces the intellectual history of a specific taxonomic error. In 1840, Salomon Muller reported—on the basis of second-hand Malay and Dayak accounts—that a one-horned rhinoceros occurred in the upper Kahayan region of Borneo. Because the animal was described as unicornate, and because the Indian Rhinoceros unicornis was still (incorrectly) believed to range as far east as the Malayan Peninsula at that time, the natural conclusion for most 19th-century naturalists was that the Bornean animal must be the Javan sondaicus. This identification was reinforced in 1869 when George Busk described two semifossil M2 molars from Sarawak as belonging to sondaicus, a paper that became highly influential and was accepted without serious challenge for decades (pp. 54–55).

The resolution came gradually. From the 1870s onward, an increasing volume of material—skulls, horns, and skins—reached European museums from Borneo, all attributable to the two-horned sumatrensis. Yet the sondaicus tradition proved remarkably stubborn: between 1884 and 1893, most authorities listed both species for the island. It was not until 1895, when Jentink and Everett independently concluded that sondaicus had never existed on Borneo, that the question was finally settled (p. 57). Rookmaaker shows that even after this resolution, the error continued to reappear in the literature well into the 20th century, with authors as late as 1962 still listing sondaicus for Borneo without qualification.

The paper is essentially a literature-based reconstruction, drawing on 19th-century proceedings, museum catalogues, and correspondence. Rookmaaker includes an appendix listing eleven specimens of sumatrensis sent from Borneo to European collections during the 19th century, providing a concrete evidential backbone to the narrative. The work is framed by the urgent conservation context of the 1970s: the Sumatran rhinoceros was already in grave danger of extinction, and the Bornean population—now estimated at no more than five to ten individuals—represented a distinct subspecies (D. s. harrissoni, Groves 1965) whose very existence had been obscured by the earlier taxonomic confusion (p. 52).

Key Findings

  • Salomon Muller (1840) was the first to report a rhinoceros from Borneo, based on a single second-hand account from a Bejadjo-Dayak who had seen a one-horned male in the upper Kahayan region; the correct identification (a sumatrensis with a poorly developed posterior horn) was never considered during the 19th century (p. 54).
  • George Busk’s 1869 description of two semifossil M2 molars from Sarawak as Rhinoceros sondaicus was not corrected until 1945, when D.A. Hooijer re-identified them as sumatrensis (p. 55).
  • The Kuching museum collection, described by Bartlett in 1891, comprised four heads and three horns, all belonging to sumatrensis—no sondaicus material was ever confirmed from Borneo (p. 57).
  • In 1896 the Amsterdam zoo purchased a young female Sumatran rhinoceros for 2,400 guilders; if it came from Borneo as Sclater stated, it is the only live rhinoceros ever exported from that island to Europe (p. 57).
  • Jentink (1895) and Everett (1893) independently concluded that sondaicus never existed on Borneo, yet the error persisted in the literature through at least 1962 (Deuve & Deuve), with authors including Sclater & Sclater (1899), Lydekker (1900), Flower (1900), and Wroughton (1921) all still listing the species for the island (p. 57).
  • The Bornean population of Dicerorhinus sumatrensis was formally recognised as a distinct subspecies (D. s. harrissoni) by Colin P. Groves in 1965, diagnosed by a markedly smaller skull with a forward-sloping occiput; the holotype is a young female skull from Suan-Lambah, Sabah (BMNH 1901.8.15.1) (p. 53).

Conclusion

Rookmaaker’s definitive takeaway is that the Bornean rhinoceros question was resolved in 1895, and that only Dicerorhinus sumatrensis—never Rhinoceros sondaicus—ever inhabited the island. The persistence of the sondaicus error in subsequent literature is attributed to the strength of the earlier tradition and the influence of Busk’s 1869 paper, rather than to any new evidence. The paper closes by noting that the surviving Bornean population constitutes the subspecies harrissoni and is in critical danger, calling for protective action even if Borneo may not be the optimal location for conservation efforts.

Context

  • The study is a literature-based review drawing on 19th-century proceedings (Zoological Society of London, Dutch natural history journals), museum catalogues (British Museum, Royal College of Surgeons, Rijksmuseum van Natuurlijke Historie Leiden, Cambridge Zoology Museum, Brussels), and correspondence; no new fieldwork was undertaken.
  • Historiographically, the article provides the first systematic account of the taxonomic confusion surrounding the Bornean rhinoceros, correcting a fifty-five-year error and clearing the ground for subsequent work on the actual distribution and conservation status of D. s. harrissoni.

References