The primary threat giant pandas face today is habitat loss. Bamboo is the main element of their diet, and bamboo forests are becoming increasingly fragmented and limited. Over-hunting in the past and a low reproductive rate also contribute to their endangered status.
Humans have destroyed large areas of pandas' natural habitat due to settlement and logging. Even where bamboo forests remain intact, they are often separated from each other by farmland or cities. This creates a problem because bamboo naturally dies off periodically. Before humans moved into the area, pandas would simply migrate to another bamboo forest nearby. With the fragmentation of their habitat, however, they often do not survive the bamboo die-offs. China has created special protective reserves for pandas, but the World Wildlife Fund estimates that only 61 percent of the wild panda population lives on them.
Although historically pandas faced serious threats from hunters, the Chinese implemented harsh penalties for people who illegally kill pandas. These measures are believed to have severely reduced or eliminated poaching. However, pandas are still accidentally killed in snares and traps set for other animals.
Pandas also have a low rate of reproduction, making it difficult to recoup population losses. Captive pandas are notoriously difficult to breed, but international collaboration has increased that rate since the 1990s.