Rhinoceros

“White” isn’t really white

Both the white rhinoceros and the black rhinoceros are gray. The “white” in the name comes from the Afrikaans/Dutch word wijd — meaning “wide” — referring to the rhino’s broad, square-lipped mouth used for grazing grass. English speakers misheard the word as “white,” and the misnomer stuck. The “black rhinoceros” was named in opposition to “white” — neither name has anything to do with actual color.

The two species are easily distinguished by the lip shape:

• White rhino — wide, square upper lip for grazing on short grass.
• Black rhino — narrow, prehensile, hooked upper lip for browsing on leaves and twigs.

A conservation paradox

White rhinos came close to extinction in the early 20th century, with fewer than 100 left in the wild. Through dedicated conservation, the southern white rhino population recovered to over 18,000 — an extraordinary rebound, and the most successful large-mammal conservation story of the 20th century.

The northern white rhino, however, is functionally extinct. The last male, Sudan, died in 2018. Two females remain alive in Kenya — Najin and Fatu — both carefully guarded around the clock. With no living males of the subspecies, the only hope for recovery is in vitro fertilization with frozen sperm: an active research program is attempting to create northern white rhino embryos and implant them in southern white rhino surrogates.

The horn that drives extinction

Rhino horns are made of keratin — the same protein as human fingernails — but in many traditional Asian medicine systems, they’re believed (without evidence) to treat fevers, headaches, and various ailments. The horn trade has been illegal under CITES since 1977, but black-market prices for rhino horn have at times exceeded the price of gold or cocaine, sustaining a poaching epidemic.

South Africa loses around 200–500 rhinos per year to poaching, despite military-style anti-poaching units, dehorning programs (cutting off horns to remove the incentive — controversial), and large-scale rangers. Some sanctuaries now keep rhinos in 24-hour guarded enclosures.

Five rhino species

There are five rhinoceros species worldwide, all imperiled:

• White rhino (Africa) — Near Threatened; ~18,000 remaining.
• Black rhino (Africa) — Critically Endangered; ~6,000 remaining.
• Indian rhinoceros (one-horned, India and Nepal) — Vulnerable; ~3,700 remaining.
• Javan rhinoceros (Indonesia) — Critically Endangered; ~76 remaining (one population).
• Sumatran rhinoceros (Indonesia) — Critically Endangered; under 50 remaining.

The Javan and Sumatran rhinos are smaller, hairier, and are the closest living relatives to the extinct woolly rhinoceros of the Ice Age.

A surprising relative

Rhinos are odd-toed ungulates (Perissodactyla) — the same order as horses, donkeys, and tapirs. Their nearest living relatives are tapirs. Hippos, despite the superficial similarity, are even-toed ungulates — closer to cattle and pigs.