How long has the platypus been threatened to be extinct?

The platypus is not listed as endangered. Platypus do not yet even qualify as threatened, although they are unofficially "vulnerable". Although very delicate creatures, sensitive to ecological changes, pollution and habitat loss, their distribution is still much the same as it was prior to European settlement, apart from in South Australia where they were wiped out last century (like many native species), being hunted for their fur. The platypus is now a completely protected species.