Inspiring: Cute Tiny Critters Eat Males That Die After Marathon Orgies, Scientists Discover

In the latest case of “WTF nature?!”, scientists in Australia have discovered that a tiny marsupial—famed for its 14-hour sex sessions ending in death for males of the species—also cannibalizes its fallen comrades.

The so-called mainland dusky antechinus is a shaggy-furred species of marsupial about the size of a mouse that is endemic to Australia. Their usual fare is insects and other hard-shelled invertebrates but they’ve been known to partake in lizards, birds, and small mammals from time to time. 

Now, in a study published in Australian Mammalogy, researchers have documented a mainland dusky antechinus feasting on a rotting member of its own species. It’s the first time biologists have observed the behavior and a rare case where they’ve managed to capture it on film. 

The animal’s claim to fame is semelparity, or suicidal reproduction. During their one-to-three-week breeding season, males and females go at it with as many mates as they can in what University of Queensland Technology biologist Andrew Baker describes as “frenzied bouts” lasting up to 14 hours.

It’s a marathon feat that takes the ultimate toll. Stress hormone and testosterone levels get so high in the tiny males’ bodies that they die from either internal bleeding, a quashed immune system, or failing livers and kidneys. It’s then up to the pregnant females to carry on the legacy and make sure the species survives to the next generation.

Their sessions are so long, and the end result so grave, because females are only fertile for a very short time, making competition among males fierce. Instead of fighting, males try to “outsex” each other.

But what of the fallen males? Previously researchers had only speculated at the possibility that males would be eaten by other Antechinus and the latest discovery was serendipitous, according to the study’s authors. 

Andrew Baker and ecologist Elliot Bowerman were hiking through Point Lookout in New England National Park, New South Wales in August 2023 when they heard a rustling in the dense vegetation underfoot. Moments later, they saw a mainland dusky antechinus dragging its dead-fellow meal. The pair whipped out their mobile phones and started recording. “[Cannibalism] is very rare to observe in the wild,” said Baker in a press release.

The deceased Antechinus had a maggot hanging from its arm, indicating that it wasn’t a fresh kill. Later on their hike, they found another dead and partially-eaten Antechinus. When Baker, Bowerman and Ian Gynther, a senior conservation officer with the Queensland Government, looked back on the footage they clearly identified the animals as from the mainland dusky antechinus species and suspected the animals were males, based on their body size and the fact that the cannabilizer was missing fur and had a damaged eye—signs of sex-induced stress taking hold. 

While the discovery was rare, it’s unsurprising, said Baker. “The males drop dead, which provides an opportunity for cheap energy gain via cannibalism for still-living males and pregnant or lactating female antechinuses,” he said. All individuals eat voraciously in the leadup to their orgies, with males eating very little during, and it's common for some males to survive for a little longer after.  

Although they didn’t observe it directly, it would also make sense for females to take the opportunity to feast on dead males because there’s a gap in food availability between the end of mating in winter and when they give birth in the spring. Another possibility is that the brown antechinus species—who live in the same area but have a slightly later breeding season—could also nibble on the odd mainland dusky drumstick. 

Dead males may therefore serve as “not only a timely and abundant energy-rich source of food… but one that does not need to be pursued or overcome before being devoured,” the authors write.

Cousins of Antechinus (animals in the Dasyuridae family) have been seen cannibalizing their fellow mates and cannibalism in general is surprisingly common in animals. Chimpanzees, lions and fish all eat their young to try and kill off babies that aren’t theirs; wild hamsters eat their young if food is scarce; female insects and spiders eat males after mating; and leopards will eat other males to ward off competition. Antechinus may be yet another case of opportunistic feasting or clever survival strategy.