A new study published last week in the peer-reviewed journal Memoirs of the Queensland Museum Nature has revealed that mouse-like creatures Dusky Antechinus continue to have sex with each other till they don’t die.

The Mainland Dusky Antechinus, which are found in southeastern Australia, already face the threat of extinction due to loss of habitat and feral pests. They have been elevated from sub-species to a distinct species. Now the researchers fear that their suicidal sex frenzies will drive them extinct.

The new species are types of antechinus, a bristly haired, mouselike marsupial that eats spiders and insects. Every year, antechinus males fight each other so that they can have sex with as many females as possible before dying.

Study’s lead author Andrew Baker of the Queensland University of Technology said, “The breeding period is basically two to three weeks of speed-mating, with testosterone-fueled males coupling with as many females as possible, for up to 14 hours at a time”.

Baker mentioned that all of that testosterone triggers a malfunction in the stress hormone shut-off switch for the males. After sex is complete, sex hormones in males cause their immune systems to collapse.

They die before the females actually give birth. The population reduces to half due to yearly male suicide mission cuts.

Although suicidal reproduction or semelparity is rare in mammals, it has been documented in these kinds of marsupials.