Fatal Attraction: These Sex-Crazed Male Marsupials ‘Do It’ to Death

Two chubby marsupial species that would literally die for 14-hour sessions of sex have been discovered Down Under, researchers report.

The new species are types of antechinuses — bristly haired, mouselike marsupials that eat creatures such as spiders and insects. Every year, antechinus males fight each other tooth and claw so they can have sex with as many females as possible before dying.

The Tasman Peninsula dusky antechinus (Antechinus vandycki) is under threat, and not just because the males have sex until they die. Gary Cranitch / Queensland Museum

After the sex is complete, with some sprees lasting as long as 14 hours, stress hormones in males skyrocket, causing their immune systems to collapse. "They all drop dead before the females give birth to a single baby," lead study author Andrew Baker, a mammalogist in Queensland University of Technology's Science and Engineering Department, said in a statement.

"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," Baker said. "But the future of each species is entrusted to the mothers alone."

Ten species of this sex-crazed marsupial had previously been known to science, with the first discovered in 1803. In the past three years, scientists have identified five new antechinus species, suggesting that the genus has more diversity than previously thought.

Like the previously known antechinus species, the two most recently discovered species — the Tasman Peninsula dusky antechinus (Antechinus vandycki) and the mainland dusky anthechinus (Antechinus swainsonii mimetes — spend two to three weeks a year in a testosterone-fueled mating marathon, the researchers said. [See photos of the antechinus in its native environment]

A. vandycki faces challenges beyond surviving a mating frenzy: Loggers are tearing apart the animal's habitat and may push the species into a threatened status, the researchers said. Moreover, three of the relatively new antechinus species, including A. vandycki, face other threats — including climate change, feral pests such as cats and non-native foxes, and habitat loss.

The study was published online May 26 in the journal Memoirs of the Queensland Museum | Nature.

This is a condensed version of a report from LiveScience. Read the full report. Follow Laura Geggel on Twitter. Follow LiveScience on Twitter, Facebook and Google+.