Everything You Need to Know About Platypus Venom and Spurs

One of nature’s most extraordinary creatures: the platypus. This semi-aquatic mammal, is not only known for its unique appearance but also for its venomous capabilities. Many are curious about the potency and effects of platypus venom, and whether it ranks as the most painful sting in the animal kingdom. Many questions arise regarding the availability of a cure or antivenom for platypus envenomation, as well as the location of the animal’s stinger.

Platypus venom is a unique substance produced by male platypuses during breeding season. It can cause severe pain to humans, but is not lethal.

The platypus is one of the rare mammals that can actually produce venom. This venom is brewed up in specialised glands linked to hollow spurs on its back legs, mainly produced during the mating season. While the venom can cause some pretty intense pain, it’s not deadly to humans. Interestingly, many ancient mammal species had similar spurs, suggesting that the platypus simply inherited this trait from its ancestors rather than developing it independently. So, rather than being a unique oddball, the platypus is more like a living relic of a once-common mammalian feature and can serve as a model for studying venom in non-therian mammals.

Spur and Crural Gland

The male platypus sports a rather noticeable spur on the inner part of each hind ankle. Adult males have spurs that are about 15-18 millimetres long and resemble a dog’s canine tooth in shape. In contrast, the spurs of young males are shorter and thicker, covered by a protective whitish layer of keratin (the same stuff in human fingernails). This keratin layer gradually chips away, starting at the tip, and is usually completely gone by the time a young male turns one. Female platypuses, whether young or old, don’t have these prominent spurs, although they do have tiny vestigial spur-like structures up until they’re about 9 months old.

The male platypus produces venom in its crural glands, which are kidney-shaped and located in the upper thigh. The venom is delivered through a spur on each hind leg. Female platypuses, like echidnas, have tiny spur buds that don’t develop fully and fall off before their first birthday. They also lack functional crural glands. The spur is connected to a small bone, allowing it to move at a right angle to the leg, giving it a greater range of attack. Normally, the spur lies flat against the leg but can be raised when needed.

Venom

Only mature males produce venom, and they ramp up production during the breeding season. It’s believed that the venom helps males compete for mates. When an adult male is touched or stroked on the belly between the hind legs, especially during mating season, it triggers a spurring response. The platypus’s hind feet rotate outwards and upwards, locking the spurs into position against the lower limb bones. The spurs are then driven inwards with significant force.

The crural gland produces venom that includes at least nineteen peptides and some non-nitrogenous components. The peptides identified fall into three categories: defensin-like peptides (OvDLPs), C-type natriuretic peptides (OvCNPs), and nerve growth factor (OvNGF). The OvDLPs are related to, but distinct from, those in reptilian venom. This is an example of convergent evolution, where venom genes evolved from existing immune system genes (defensins). A unique aspect of the venom is the presence of a D-amino acid, the only known instance in mammals. The venom seems to be related to that of various species outside the platypus’s evolutionary line, like certain fish, reptiles, insectivores, spiders, sea anemones, and starfish.

The venom’s chemicals have various effects, from lowering blood pressure to causing pain and increasing blood flow around the wound. Coagulating effects have been observed in lab animals, but not consistently. Unlike snake venom, platypus venom doesn’t seem to have a necrotising component. Muscle wastage observed in envenomated humans is likely due to the inability to use the limb while the venom’s effects last. It’s unclear whether the pain is due to the swelling around the wound or if the venom directly affects pain receptors.

Platypus venom has similar effects and substances to reptilian venom but serves a different purpose. It’s not life-threatening but can cause significant impairment, even temporary paralysis. The venom isn’t used to disable or kill prey but rather as a defensive mechanism. Only males produce this venom, and its production increases during the breeding season, suggesting it’s used to assert dominance and control territory. While the venom might be used for mating purposes, it could also serve defensive functions against predators like crocodiles, Tasmanian devils, and raptors.

Effect on Humans and Other Animals

Though strong enough to paralyse smaller animals, platypus venom isn’t lethal to humans. However, it can cause excruciating pain, enough to incapacitate a person. Swelling quickly develops around the wound and spreads outward. Case studies show that the pain can turn into long-lasting hyperalgesia, usually lasting from a few days to a few weeks, sometimes months. A 1992 clinical report indicated that the severe pain didn’t respond to morphine.

If you ever need to handle an adult male platypus, the safest way is to grasp the end half of the tail, which the spurs can’t reach. To avoid getting spurred, never try to hold or support an adult male (or any platypus of unknown age and sex) from below. Instead, lift the animal by firmly holding the end half of the tail. By holding the platypus this way, you should be able to easily see if it has spurs.