The IUCN, which works with governments, the United Nations and environmental groups, also warned that 94 per cent of wide-eyed primate lemurs are threatened with extinction.

Of the 101 surviving species, 22 are under threat - including the biggest, the large-bodied Indri, and the smallest, Madame Berthe's mouse lemur - the Switzerland-based body said. Lemurs are threatened by destruction of their tropical forest habitat in Madagascar.

Political uncertainty and rising poverty have accelerated illegal logging, the IUCN explained, adding that hunting of the animals for food had also emerged as a serious issue.

In the plant world, the group warned that close to 80 per cent of temperate slipper orchids now face extinction.

The finding was based on a global assessment of the species, which are easily recognisable by their slipper-shaped flowers, which trap insects to ensure pollination. They are found in North America, Europe and temperate regions of Asia.

The IUCN blamed habitat destruction and excessive harvesting of wild species for sale.

"What was most surprising about this assessment was the degree of threat to these orchids," said Hassan Rankou of the IUCN's orchid team, which is based in the Royal Botanic Gardens in London.

"Slipper orchids are popular in the multi-million-dollar horticultural industry. Although the industry is sustained by cultivated stock, conservation of wild species is vital for its future," he said.

Among the most at-risk species are the freckled cypripedium, with less than 100 left in China's Yunnan and Ha Giang province in Vietnam.

Turning to the globe's rivers and oceans, the IUCN said that the Japanese eel - a traditional delicacy in Japan and the country's most expensive food fish - was also in danger.

It had been hit by habitat loss, overfishing, barriers to migration, pollution and changes to oceanic currents.