HAVING so much sex you die might sound like a reasonable way to go, but for a marsupial species that lives south-west of Gladstone, it is putting them in danger of being wiped out completely.
The Silver-headed Antechinus, which is found in the eastern escarpment of Kroombit Tops National Park, is listed as threatened.
Queensland University of Queensland mammologist Dr Andrew Baker said the Kroombit Tops species had one of the smallest distributions of any Australian mammal, just a few square kilometres.
Dr Baker said the annual suicidal sexcapades of antechinus made them more vulnerable to population extinctions.
Every year, all antechinus males fight ferociously for sex - then die.
"The breeding period is basically two to three weeks of speed-mating, with testosterone-fuelled males coupling with as many females as possible, for up to 14 hours at a time," Dr Baker said.
"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.
"This yearly male suicide mission, which halves each antechinus population, means the mums have enough spiders and insects to eat while they raise the next precious generation.
"But the future of each species is entrusted to the mothers alone."
Now, Queensland scientists have discovered two more species of suicidally-sexed carnivorous marsupials, one on Tasmania and one on the mainland.
The team's latest discoveries have been published in the peer-reviewed journal Memoirs of the Queensland Museum - Nature.
Dr Baker's team is also seeking to have all three threatened antechinus species added to Australia's federal threatened species list, which will help ensure their protection.
"Nine in 10 Australian mammal species are unique, yet they are vanishing before our very eyes," Dr Baker said.
"In a country with the worst mammal extinction rate anywhere on earth, Australia is in the midst of unprecedented loss of its biological treasures.
"Millions of native mammals likely fall victim every night to feral cats alone. Other introduced ferals, such as European foxes and poisonous cane toads, account for the deaths of millions more."
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