The Bornean Bay Cat is the mystery cat of the family. Its description rests on just a few skins and skulls, most collected in the late 1880s, scattered in several museums around the world. Tissue and blood samples for genetic analysis were acquired only in late 1992, when a female captured by trappers on the Sarawak-Indonesian border was brought to the Sarawak museum on the point of death. The cat weighed 1.95 kg, but was estimated to have weighed between 3-4 kg when healthy.

The Bornean bay cat has two color phases: chestnut-red, the more common, and grey. The coat of the 1992 female was speckled with black markings. Her tail was long: at 39 cm, 73% of head-body length (53 cm). On all specimens, the backs of the rounded ears are darker-colored, and a whitish stripe runs down the ventral surface of the terminal half of the tail. The bay cat resembles the Asian golden cat not only in these characters, but also in skull dimensions, and may well be an island form. The Asian golden cat occurs widely throughout South-East Asia, including Sumatra but not Borneo. Borneo has been separated from Sumatra and other islands on the Sunda Shelf for 10,000 - 15,000 years. With blood samples taken from the 1992 specimen, genetic testing has confirmed that they are indeed a unique species, and therefore a highly endangered one.

There are thought to be seven or eight locations on Borneo where the bay cat may have been seen. Habitat preference seems to be highland areas of rocky limestone situated on the edge of dense jungle, hill forests up to 500 metres, and lowland and swamp forests. Early naturalists reported that these cats were found only in dense forest. At least three of the specimens were collected along rivers, but it is unknown whether this reflects a habitat preference or the collector's most effective method of transport in the difficult Bornean terrain.

Indonesian: The Bornean bay cat is found only in Borneo.

Although Borneo has 25 wildlife reserves on paper, only three are actually in existence, with the others only proposed. All of them have been encroached upon by human settlement and logging. Loss of habitat would seem to be the main threat to this little known species, and they may have always been rare. The World Conservation Union Cat Specialist Group has placed a high priority on field research on this species. Fully protected over most of their range, CITES has placed the Bornean bay cat on Appendix II, due to lack of data.

Alderton, David. Wild Cats Of The World. New York: Facts on File, 1995

Nowak, Ronald. Walker's Mammals Of The World. Baltimore: Johns Hopkins University Press, 1999