Giraffes are being pushed towards extinction, with the global population plummeting by up to 40 per cent in the past 30 years, conservationists have said.

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.

And according to a German evolutionary biologist Axel Janke giraffes are going through a silent extinction, with the fact flying under the radar of even the most devoted of researchers.

“Only 400 scientific papers have been written about giraffes, versus 20,000 papers on white rhinos,” he told National Geographic.

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 habitat loss and unsustainable trapping for trade.

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, with more than one in 10 found to be at risk of dying out.

IUCN director general Inger Anderson says many species are slipping away before they can even describe them.

“This IUCN Red List update shows that the scale of the global extinction crisis may be even greater than we thought,” Anderson said.

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 are threatened with extinction, being classed as critically endangered, endangered or vulnerable.

Giraffes, 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 151,700 to 163,450 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 per cent 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.

When giraffes get angry