The population of Australia's feral camel has dropped by a quarter, but still remains the world's largest wild herd, according to a survey by the Australian Feral Camel Management Project (AFCMP).

The feral population, which was estimated around one million in Australia, has gone down by 250,000 placing the number now at 750,000 owing to drought and culling of the desert animals.

"Between 2001 and 2008, it was estimated that there could have been as many as a million feral camels in the outback," Jan Ferguson, from the not-for-profit company Ninti One, which manages the AFCMP said in a statement. "Since then, however, there has been a major drought, the feral camel management programme has come into effect and population survey techniques have been improved."

The feral camels have faced a high mortality rate during the drought, and some of them have been killed under a plan by the AFCMP. Feral camels are an invasive species and cause damage to the vegetation, trees and shrubs mainly when there is a drought. They are also potential carriers of diseases, and are a big concern for native animals and plants as these camels are capable of degrading the waterholes during drought thus threatening the destruction of the native species.

These camels are capable of travelling more than 40 miles in one day on harsh terrains. They are spread across 1.2 million square miles in various places including Western Australia, Northern Territory, South Australia and Queensland.

Earlier in 2009, the Australian government announced culling of these wild herds as they started damaging homes in search of water.

Although there is a significant drop in the feral camels, Ferguson believes more action needs to be taken to control the camel density that is high in some areas. In order to learn the movements of the camels, AFCMP is tracking 50 feral camels that are fitted with special collars.