The good news: Scientists have discovered two new species of dusky antechinus to add to the three others found in the last few years for a 50% boost in diversity among the Australian mammals. The bad news: Three of the new species are already threatened by climate change, feral animals, and loss of habitat as state forests are logged. If that weren't enough, the animals are what Phys.org calls "suicidally-sexed carnivorous marsupials." Each year, antechinus males spend two to three weeks mating with as many partners as possible, for up to 14 hours per session. "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," researcher Andrew Baker explains. While mom and baby have plenty to eat as a result, the annual suicide mission puts the animals in danger of population extinctions.
The males "get gastric ulcers, internal bleeding, their fur will fall out in patches, basically any disease that they get or any parasites they've got they've got no ability to fight with their immune system, it completely shuts off," Baker tells the Brisbane Times. "The future of each species is entrusted to the mothers alone." Researchers have applied for threatened status for three species found in Australia: the black-tailed antechinus and silver-headed antechinus, which inhabit just a few square kilometers in southeast Queensland, and the Tasman Peninsula dusky antechinus. Scientists next hope to find more unidentified antechinus species, track their geographical range, and identify protection strategies. "In one sense it makes you wonder how many species there are to discover but in another sense you wonder if they might go extinct before we actually discover them," Baker says. (The marsupials share a common interest with this porpoise.)