Wild giraffe numbers have plummeted by 40 percent in the last three decades, and the species is now "vulnerable" to extinction, a top conservation body warned Thursday.
The population of the world's tallest land mammal dropped to below 100,000 in 2015, mainly due to shrinking habitat and illegal hunting, the International Union for the Conservation of Nature (IUCN) reported.
"These majestic land animals are undergoing a silent extinction," Julian Fennessy, co-chairman of the IUCN's specialist group on giraffes, said in a statement.
Previously, giraffes held the status of "least concern" on the IUCN's Red List, which tracks the conservation status of fauna and flora and ends with the category "extinct."
Giraffes are spread out across southern and eastern Africa, with smaller pockets in west and central Africa.
RELATED: Extremely Rare White Giraffe Spotted in Tanzania
Of nine distinct subspecies, four small populations saw increases. But four larger ones experienced sharp declines, and one remained stable, according to the report.
Numbers have crashed in 30 years from an estimated 157,000 to about 97,500 last year, the IUCN said.
The main culprit is the ever-expanding human population, which has caused a spike in poaching and encroachment upon the giraffe's natural habitat.
The report was part of an update of the Red List, unveiled at a meeting in Cancun, Mexico of the 196-nation Convention on Biological Diversity.
The global assessment now covers 85,604 species of plants and animals, of which 24,307 face the threat of extinction.
"Many species are slipping away before we can even describe them," said IUCN director general Inger Andersen.
The update "shows that the scale of the global extinction crisis may be even greater than we thought," she said.
Earth has entered a "mass extinction event" in which species are disappearing 1,000 to 10,000 times more quickly than just a century or two ago, according to scientists.
There have been six such wipeouts in the last half-billion years, some of them claiming up to 95 percent of all lifeforms.
RELATED: DNA Shows Four Giraffe Species, Not One
A recent analysis in Nature of nearly 8,688 "threatened" or "near-threatened" animal and plant species showed that three-quarters are over-exploited for commerce, recreation or subsistence.
More than half suffer the conversion of their natural habitats into industrial farms and plantations, mainly to raise livestock and grow commodity crops for fuel or food.
A fifth of species are affected by climate change.
WATCH: Why Aren't Modern Animals as Large as Dinosaurs?