Three hours less a night: Male broad-footed marsupials sacrifice sleep for more sex

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In order to have more time for sex during mating season, male broad-footed marsupials sometimes sacrifice several hours of sleep per night. That’s the conclusion of an international study published Thursday in the journal Current Biology.

Only the movements and sleep of Swainson and gray marsupial mice (Antechinus swainsonii and A. agilis) living in Australia were measured. According to the researchers, this is the first study to provide direct evidence of this type of sleep restriction in a land-dwelling mammal.

“Using a combination of techniques, we showed that males sleep less during mating season,” said lead author Erika Zaid, of La Trobe University in Melbourne, Australia. One man even cut his sleep by half.

Men slept three hours less per night

“In humans and other animals, a reduction in the normal amount of sleep results in decreased performance while awake, an effect that increases each night. And yet the broad-footed marsupial mice did exactly that: They slept three hours less each night, every night for three weeks.” Sleep duration did not change in women.

For small marsupials, it’s a balance between sleep and reproduction, and as the study notes, it’s likely due to strong sexual selection: Broad-footed male marsupials live only one mating season, after which they die. This rare reproductive strategy is also called semelparity. According to the study’s authors, males compete to contact as many females as possible to maximize their chances of successful reproduction during their first and only mating season.

Animals die after mating

“It’s actually a bit surprising that animals don’t sacrifice more sleep during mating season because they’re going to die soon anyway,” Zaid said. “This way, most of their sleep is preserved, which highlights the basic functions of sleep.”

It remains unclear why males die at around one year of age, after a three-week mating period, according to the study. Lack of sleep is probably not a determining factor; Animals that slept less were no worse off than animals that slept more. (SDA)

Source : Blick