Animals and Insects

Meet the cute little marsupials that prioritize sex over sleep

These passionate little creatures usually sleep for 15 to 17 hours a day, but during mating season, some can slash their sleep time by more than half.

A picture of a dusky (Antechinus swainsonii) and a agile (A. agilis) antechinus.
A dusky antechinus and an agile antechinus.
Current Biology
SMS

You know the song: "Live fast, die young, these furry little Australian marsupials do it well ..." Okay, maybe it doesn’t go quite like that, but you get the gist.

A group of scientists have discovered that male dusky and agile antechinuses, which resemble mice, prioritize mating over sleeping, and, sadly, after the baby-making season, they die.

In a report published on Thursday in the journal Current Biology, the researchers observed that the rise in mating activity was linked to an increase in testosterone levels.

“In a trade-off between the neurophysiological requirements for sleep and evolutionary necessity for reproduction, strong sexual selection might drive males to sacrifice sleep to increase access to fertile females and ultimately maximize their fitness,” the study noted.

Researchers say that this happens because male antechinuses are semelparous, meaning they only live through a single mating season, while females can live up to 2 years. Overall, scientists found that the males of the species, which live for about 11–12 months total, sleep three hours less per night during their final three weeks of life. 

While three hours less doesn't sound like much, keep in mind that the average sleeping time for these little sex addicts is between 15 to 17 hours, and according to the study, one of the males they observed significantly cut its regular sleeping hours by more than half once mating season started. 

“They stay awake to secure paternity before they die,” Erika Zaid, a wildlife biologist at La Trobe University in Australia and the study’s lead author, told Scientific American. “It’s a huge trade-off, but the most important thing for them is to pass on their genes.”

But why do they have to die? 

Well, too much stress can pretty much kill anybody, if we're being honest. But, according to actual science, it's due to "high corticosteroid levels."

During mating season, males give it their all, quite literally, to mate with as many females as possible. This elevates corticosteroids, which weakens the immune system and animals' ability to respond to inflammation, part of a chain of events that leads to fatal stress-induced organ failure, infections, and parasite infestation, the report says. 

So, what did we learn? Too much of anything, even if it's to keep your species alive, can kill ya!