The platypus is a very unusual mammal. It is one of the few mammals that lays eggs rather than giving birth to live young. This native of Australia is semi-aquatic and possesses a duck's bill, a beaver's tail and otterlike feet. It is also one of the only venomous mammals. It is important to understand why and how a platypus would attack.
Venom Production and Spur
Only male platypuses produce venom, which is delivered via spurs, or claws, on its hind legs. The poison is made in the crural glands in the upper thigh of the hind legs. When a platypus is going to attack, the spur goes from its usual position of flat on the leg to pointing up. The venom, which is made up of peptides, causes a fall in blood pressure, pain, and increased blood flow around the wound. It is used only as a defense mechanism and not used to kill prey.
Platypus venom is not lethal to humans, but it can kill smaller animals. However, it does cause a very severe reaction in humans, and it needs to be treated as soon as possible with anti-venom.
The first symptom is extreme pain, which is designed to incapacitate the victim. Swelling soon follows. This starts at the entry wound but will spread.
Although there is very little risk of fatality--there have been no reported human deaths from platypus venom--some studies have shown it can lead to long-term hyperalgesia. This is a condition in which the victim has an increased sensitivity to pain. This condition should last only a few days to a few weeks, but it has been known to last for a few months.