Scientists from the Queensland University of Technology have discovered a new species of marsupial from Australia, which quite literally mates itself to death.
Life is short and sex-centered for the genus Antechinus. Six months after they’re born, the small, carnivorous marsupials reach adulthood. For five more months, they gain weight that they’ll burn off having sex, says mammalogist Andrew Baker of Australia’s Queensland University of Technology. Then the animals enter “a one- to three-week period where they spend all their time mating.” Males fight over females, promiscuous mating ensues, and a single coupling can last 14 hours. Small wonder, as Baker observes, that “both sexes become really stressed.”
Males relentlessly bound from partner to partner, as massive hormone releases in their bodies cause their immune systems to crash and their fur to fall out. They bleed internally. Some males even go blind, yet still stumble around the leaf litter hoping for one last tryst. In a few short weeks, every single male lies dead, leaving the females to raise their offspring. And so it seems that in perpetually dangerous Australia, even the sex can kill you.
For these three weeks of sexual kamikaze, antechinus males are concerned with nothing–absolutely nothing–other than mating with as many females as they possibly can. Ecologist Andrew Baker of Australia’s Queensland University of Technology, who studies these critters’ astonishing habits, has even picked up a copulating pair, who ignored him entirely and went about their business in his hands. “It’s pretty frenzied,” said Baker. “There’s no courtship or anything like that. The males basically just grab the females and go for it.”
The manner of synchronised suicide in males is quite horrible to see. Males lose their fur and can develop ulcerations and gangrene.
Biologists used to assume that these animals fight during the mating season but we now know they don’t. Despite the time pressure and rampant testosterone, overt contests between males are virtually absent, and they appear positively friendly towards one another.
“Ultimately, the testosterone triggers a malfunction in the stress hormone shut-off switch; the resulting rise in stress hormones causes the males’ immune systems to collapse and they all drop dead before the females give birth to a single baby,” said the lead researcher, Andrew Baker.
There is some logic to this evolutionary strategy; the yearly ‘suicide mission’ halves the population of the species and allows the females to have enough food to raise the next generation.
The Tasman Antechinus is now threatened by climate change and logging as well as its tendency to halve its population every year.