Erika Zaid CC BY-SA
- Small male Australian marsupials prefer to forgo sleep for sex.
- During their three-week mating season, they sleep three hours a night less than usual.
- Female antechinuses survive for longer, and may feast on males once they die.
Male antechinuses have adopted an interesting survival strategy: foregoing sleep for sex during the mating season.
The surprising evolutionary move was discovered after a multi-year-long study that arduously tracked the small Australian marsupials through the coastal forest.
For the length of its three-week mating season, the male antechinus sleeps on average 12 hours a night, compared to its usual 15 hours, before dying and being eaten by its mate.
"In humans and other animals, restricting the normal amount of sleep leads to worse performance while awake, an effect that compounds night after night," said lead author Erika Zaid in a press release.
"And yet, the antechinus did just that: they slept 3 hours less per night, every night, for 3 weeks," said Zaid, who is a graduate researcher of animal, plant and soil sciences of La Trobe University in Melbourne.
This is the first study to show land-dwelling animals sacrificing precious hours of slumber for reproduction.
"They have this super bizarre breeding system, which is quite common among flies and some fish, where the males live one year, have a single shot at securing all their reproductive success, and then they die," John Lesku, author on the study and zoologist at La Trobe University, told The New York Times.
Like fish and flies, antechinus live short lives. Females live just two years, while males die shortly after the breeding season.
The male corpses may provide a source of food for the females, according to a study published Jan. 18 in the journal Australian Mammalogy and reported by LiveScience.
"It is actually a little surprising that these animals do not sacrifice even more sleep during the breeding season, since they will soon die anyways," Zaid says. "In this way, keeping much of their sleep intact reveals the essential functions that sleep serves."
Still, for most animals, loss of sleep is a serious business. If humans were to extend their waking hours in the same way, that would cause a loss of focus that is equivalent to being lightly intoxicated.
The effect of the loss of sleep doesn't reset in the morning but instead is compounded every night.
The question, then, is how do these small creatures survive for three long weeks on relatively little sleep, and does it contribute to their short life spans?
"Three hours of sleep loss is not lethal in any animal we know of," Lesku said.
"So what's killing these males after one year? These males are just programmed to die, to end their evolutionary longevity after one year."
The study was published Thursday in the peer-reviewed journal Current Biology.