The world's tallest land mammal has been classed as vulnerable to extinction on the latest global Red List of Threatened Species, following declines driven by habitat loss, illegal hunting and civil unrest in the African countries where it lives.
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The assessment also revealed a worsening situation for African grey parrots, regularly kept as pets and with the ability to mimic human speech, which are now classed as endangered because of unsustainable trapping for trade and habitat loss.
More than 700 newly recognised bird species have been assessed for the new update of the Red List, produced by the International Union for Conservation of Nature (IUCN), with more than one in 10 found to be at risk of dying out.
IUCN director general Inger Anderson said: "Many species are slipping away before we can even describe them.
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"This IUCN Red List update shows that the scale of the global extinction crisis may be even greater than we thought."
She urged governments at the latest meeting of the United Nations Convention on Biological Diversity, which aims to ensure the conservation and sustainable use of nature, to step up their efforts to protect the planet's wildlife.
There are now 85,604 species assessed for the Red List, of which more than a quarter - 24,307 - are threatened with extinction, being classed as critically endangered, endangered or vulnerable.
Giraffes (Giraffa camelopardalis), widespread across southern and eastern Africa with smaller sub-populations in west and central Africa, are now considered to be at risk.
Numbers have declined from around 151,702 to 163,452 animals in 1985 to 97,562 individuals in 2015, the IUCN said, with a growing human population having a negative impact.
The loss of habitat through expansion agriculture and mining, illegal hunting, increasing conflict between people and wildlife and civil unrest are all taking their toll.
The latest Red List also includes the reassessment of all bird species, including 742 newly recognised birds, 11% of which are under threat, including the Antioquia wren which is endangered as a single dam project could wipe out half its habitat.
Wild oats, barley, mango and other wild relatives of crops that humans rely on have been assessed for the first time for the Red List. The species are increasingly important to food security, as they could provide new varieties that are more resilient to extreme conditions such as drought.
The assessment listed four mango species as endangered and the Kalimantan mango was classed as extinct in the wild.
A wild relative of the chickpea that is native to Iran and Turkey has been listed as endangered due to the conversion of its habitat for agriculture.
A Japanese relative of asparagus, hamatamabouki, is also listed as endangered due to habitat loss, while the anomalus sunflower is classed as vulnerable.