Why are platypuses vulnerable?

Answer 1

Platypuses are not "poisonous", but adult males have venomous spurs on their ankles. Through this spur, they can deliver a venom strong enough to kill a small dog, and to cause almost paralysing agony to an adult human. Also, platypus venom contains a protein which lowers blood pressure, also inducing shock.

It is uncertain why or how this spur is used, but it is believed to be a defence mechanism for this otherwise vulnerable animal.

Answer 2

The Australian Government lists the platypus as "common but vulnerable". The International Union for Conservation of Nature lists the platypus as "least concern". In the past, the platypus came close to extinction because it was prized by its fur, 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. 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. The introduction of red foxes as a predator for rabbits may have had some impact on platypus numbers on the mainland, so foxes are regarded as a threat. Feral cats are another threat, but the platypus's principal threat comes from humans. Also, the use of fishing nets in freshwater creeks and rivers resulted in large numbers being drowned, but this practice has been banned.

Natural threats to the platypus include snakes, water rats, goannas, spotted quolls, eels, hawks, owls and eagles. In the north of its range, dingoes are another predator. Lower platypus numbers in far northern Australia are possibly due to predation by crocodiles. On occasion, large eels have been thought to take platypuses, which may be only half the length of a freshwater eel.

Another threat to the platypus is flooding. Young platypuses may be washed out of their burrows when floodwaters come, and few of these survive.

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.

Answer 3

The hollow spurs on their hind legs are connected to a sac which has venom in it and the venom can kill an animal up to the size of a small dog.