Besides the rhino, the International Union for Conservation of Nature (IUCN) has removed humback whales and African elephants, among others, from its Red List of endangered species, NGO Wildlife Trust of India (WTI) said in a statement.

The IUCN observed that these species have shown signs of recovery in the wild following strict protection measures in range countries.

They are currently placed under the IUCN's "genuine improvement" list that was decided Oct 6 at a meeting in Barcelona, Spain.

However, species like the common leopard, fishing cat, sambar, Chinese pangolin and greater slow Loris, which are also found in India, are facing increased threats, IUCN said.

The group warned that one in four species of mammals in the world are facing extinction.

Meanwhile, the IUCN has named Ashok Khosla, chairman of Development Alternatives, a Delhi-based NGO, to head the group. He will replace Valli Moosa.

However, the IUCN's decision was criticised by conservationists here. They said the delisting of the species from the Red List would make the species more vulnerable, as the threat from poaching has not ceased across their habitats.

"The rise in rhino poaching over the last two years in Assam's Kaziranga National Park makes the 'demotion' from the Red List even more inexplicable," said WTI executive director Vivek Menon. Rhinos in Kaziranga are now at greater risk, he added.

According to an estimate, at least 23 rhinoceroses have been killed in the park last year.