Male Platypuses Have Venomous Spurs on Their Ankles

The platypus is already one of nature's strangest creations—a duck-billed, beaver-tailed, egg-laying mammal that looks like it was assembled from spare parts. But here's the kicker: the males are also venomous. Each male platypus has a hollow spur on the inside of each hind ankle, connected to kidney-shaped venom glands in the upper thigh.

These aren't decorative. When threatened or competing for mates, a male platypus can deploy these spurs like switchblades, delivering a cocktail of at least 19 different peptides directly into its victim.

The Pain That Morphine Can't Touch

While platypus venom won't kill a human, it causes pain so severe that standard painkillers are useless. A 1992 clinical report documented a victim whose excruciating pain didn't respond to morphine. Keith Payne, a Victoria Cross recipient who'd been struck by shrapnel in combat, said the platypus sting hurt worse—and he was still in pain a month later.

The pain can develop into long-lasting hyperalgesia (heightened pain sensitivity) that persists for weeks or even months. Swelling is immediate and intense, and muscle wasting can continue long after the initial injury.

Battle Scars of Breeding Season

Only males produce venom, and production peaks during breeding season (roughly June through October in Australia). Female platypuses are born with rudimentary spur buds, but these drop off before the end of their first year, and they never develop functional venom glands.

The purpose? Male competition. Field observations show:

• Increased spurring behavior during breeding season
• High incidence of spur marks on male platypuses
• Venom potent enough to paralyze smaller animals and immobilize rivals

This is biological warfare for mating rights. The spurs are attached to small articulating bones that allow them to swing at right angles to the leg—perfect for grappling with a competitor in the water.

One of the Few Venomous Mammals

Venomous reptiles and insects are common, but venomous mammals are rare. The platypus shares this exclusive club with a few shrew species, solenodons, and slow lorises. What makes the platypus unique is the delivery mechanism—most venomous mammals use their bite, but the platypus uses specialized leg spurs.

The venom itself is a complex chemical weapon. Scientists have identified three main categories of peptides: defensin-like peptides (OvDLPs), C-type natriuretic peptides (OvCNPs), and nerve growth factor (OvNGF). These evolved through gene duplication and functional diversification—nature's way of weaponizing defensive proteins.

A Silver Lining for Diabetes Research

There's one surprising upside to this painful adaptation: medical research. Australian scientists discovered that platypus venom contains a hormone called GLP-1 (glucagon-like peptide-1) that promotes insulin release. This same hormone is used in diabetes treatments, but the platypus version is more stable and longer-lasting than the human form.

So while you definitely don't want to get spurred by a male platypus, his venom might one day help treat diabetes. Nature's weird, painful gifts sometimes come with unexpected benefits.