Three of the world’s five living rhino species are currently listed as Critically Endangered: the black rhinoceros, Javan rhinoceros and Sumatran rhinoceros.
The other two species have less severe species-wide classifications. The greater one-horned rhinoceros is Vulnerable, while the white rhinoceros is Near Threatened overall. Those labels can obscure serious differences within a species: the northern white rhino subspecies is functionally extinct in the wild, with only two known females remaining in captivity.
Rhino populations have been reduced by habitat loss, fragmentation and poaching for their horns. The horn is made of keratin, the same protein found in human hair and fingernails, despite persistent—and scientifically unsupported—claims about medicinal benefits. Stronger law enforcement, protected areas and carefully managed breeding have helped some populations recover.
The number three refers to species, not every rhino subspecies or population. That distinction explains why a species can be classified as Vulnerable overall while one of its subspecies faces a much more extreme extinction risk.