The koala bears are some of the most beautiful animals on the entire planet, and yet they are now threatened with extinction due to loss of habitat and human activities. A new report provides a bleak perspective to their future, showing that the bears could disappear completely within less than 30 years. The most severe situation is recorded in Australia, where declines in populations are very steep. Environmentalists say that, unless action to curb the koalas' demise is not taken urgently, they will soon be nothing more than a memory, the BBC News reports.

According to the Australia Koala Foundation (AKF), the numbers of wild koalas in the country may have plummeted by more than 50 percent within the past six years alone. The primary causes for the deaths were identified in climate change, bushfires, and human-conducted development in regions naturally inhabited by the animals. Diseases such as chlamydia were also identified as one of the leading causes of death among the marsupial herbivore.

The last estimates that the AKF and other organizations released on koala bears put their numbers somewhere around 100,000 in the wild, but the recent survey identifies no more than 43,000 individuals. Some 1,800 sites and 80,000 trees were analyzed during the latest investigation, which is one of the most thorough ever conducted. The researchers involved collected field samples from all the location, and derived the numbers of koalas based on the measurements.

Deforestation and warmer weather have made the koala's main source of food, eucalyptus leaves, less nutritious, which means that many of the marsupials also suffer from malnutrition. In certain area in northern Queensland, scientists could not find a single koala after 4 days of searching in spite of the fact that they knew more than 20,000 individuals lived in those woods less than 5 years ago. “The koalas are missing everywhere we look. It's really no tree, no me. If you keep cutting down trees you don't have any koalas,” explains Deborah Tabart, the chief of the AKF.

The animals are known for being very fussy about what they eat. They relay solely on eucalyptus leaves for their sustenance. When the leaves can't be found, the marsupials most often starve until supplies become available, or until they die out.