A conservation program has been launched by the Zoological Society of London (ZSL) to protect some of the world's weirdest and most endangered species.

The Evolutionary Distinct and Globally Endangered (Edge) project will highlight the threat to unique species such as the pygmy hippopotamus and the bumblebee bat.

The project focuses on bizarre and unusual animals with unique evolutionary histories. They are genetically distinct, have few close relatives, and face the real threat of extinction.

"We will be working to protect some of the world's most extraordinary species," said Jonathan Baille, the scientist leading the project in a statement. These will include "Giant venomous shrew-like creatures, matchbox size bats and egg-laying mammals, all of which are teetering on the edge of extinction," he said.

The Edge team measured just how evolutionary distinct different species are. They then looked at how significant the risk of extinction was for the species and came up with 564 species that fall within the "Edge" definition.

The ZSL project will focus on the top 100 species. In its first year, 2007, it has chosen to highlight 10 species. These include the bumblebee bat, believed to be the world's smallest mammal, which last shared a common ancestor with another bat 43 million years ago. Its habitat in the caves of Thailand and Burma is now threatened by forest fires.

The slender loris, a shy primate with gigantic eyes, is also facing extinction due to deforestation in its native Sri Lanka. Its unique genetic heritage can be traced back to fossils from the Early Miocene period -- 20 million years ago.

Other Edge animals include the Bactrian camel, the long-beaked echidna, the long-eared jerboa, the Yangtze River dolphin and the Hirola antelope. The Edge team is also planning to set up similar schemes for reptiles, birds and amphibians.

"If you were to think about Edge species in terms of the art world, it would be like losing the Mona Lisa," Baillie told BBC News. "They are totally irreplaceable and unique."

The project will send scientists to each of the animal's natural habitats to set up action plans. The project aims to establish conservation plans for all the top 100 Edge creatures over the next five years.

"It is a tragedy that many Edge species are being ignored and are slipping silently towards extinction," Baille emphasized. "It is essential that we now focus our energies on highlighting and protecting these remarkable species before it is too late."

It may already be too late for one of the top 10 Edge animals: the Yangzte River dolphin, also known as the baiji. Conservationists and scientists launched a big search for the dolphins in December of last year but could not find any in China's Yangzte River -- the only habit for these rare creatures. They concluded that the baiji was in all likelihood already extinct.