Being an entirely endemic and rare land mammal, "B. mindorensis" stands as an extremely vulnerable species. Currently, it is classified as a critically endangered species and has been so since 2000 by the IUCN on its IUCN Red List of endangered species. Awareness of the conservation status of "B. mindorensis" began in 1965, when it was classified as status inadequately known by the IUCN. Enough data were gathered on the tamaraw population by 1986, and the IUCN conservation monitoring center declared the species endangered. Throughout succeeding surveys conducted in 1988, 1990, 1994 and 1996, the species remained listed on the Red List as "endangered". The relisting of the species in 1996 fulfilled the IUCN criteria "B1+2c" and "D1". Criterion "B1" indicated that the species' range was less than 500 km2, and is known to exist in less than five independent locations. A noticed continuing decline in the population fulfilled sub-criterion "2c", given the condition of the population's sole habitat. Criterion "D1" essentially required that a population be composed of less than 250 mature individuals; individual counts of the "B. mindorensis" population at the time figured significantly lower than this. In 2000, the tamaraw was relisted on the Red List under the more severe "C1" criteria. This was due to estimates that the population would decline by 20% in five years or within the timespan of two generations.