Answer:
The platypus, although found only in the country of Australia (which includes the island state of Tasmania) is not endangered. It is not listed on the IUCN Redlist (endangered species list).
There was a time when the platypus was under threat, being particularly prized for its fur years ago. In the past it came closer to extinction but it now has protection by law in the National Parks and Wildlife Act of 1974 (from hunters and fishermen), and the population has grown back to a healthy size. However, there are concerns regarding the destruction of their habitat and awareness of this problem is increasing. The use of fishing nets is still something of a problem, even though it is illegal now to use fishing nets in freshwater rivers and creeks, as the platypuses can become entangled.
The Australian Government lists the platypus as "common but vulnerable". The International Union for Conservation of Nature lists the platypus as "least concern". Platypuses are now strictly protected by law. The platypus is vulnerable because of habitat loss through deforestation, dams and irrigation projects. They have disappeared from South Australia.
Tasmanian platypuses are subject to a disease caused by the fungus Mucor amphibiorum, which has fortunately not migrated to the mainland. Affected animals often develop skin lesions or ulcers, and the biggest threat to their survival arises from secondary infection. This can affect the platypus's ability to maintain body temperature and to hunt properly for food on the bottom of rivers and creeks.