Some will say that the end justifies the means. This is a small Australian marsupial called antechinus. Sacrifice hours of sleep per night to have more time for sex during mating season. The marsupial that does not sleep to reproduce seems to have its priorities clear.
Researchers at La Trobe University say so in the journal 'Current Biology'. Their multi-year study shows direct evidence of this type of sleep restriction in any land mammal. It's a trade-off between sleep and reproduction. It appears to be driven by strong sexual selection.
Intense season
Using a combination of techniques, they showed that males lose sleep during the breeding season. They cut their sleep in half during this mating period. In humans and other animals, restricting the normal amount of sleep leads to worse performance while awake. The effect worsens night after night. But the antechinus did just that. “They slept 3 hours less per night, every night, for 3 weeks.”
Antechinus are strange in other ways too. Males only reproduce once in their life and live only 1 year. Females can live 2 years. The males usually die at the same time, just after their single, short, intense mating season. During the breeding season, males physically compete for access to more females.
The researchers used accelerometry to track the marsupials' movements. They also used electrophysiology and metabolic measurements to quantify how much the animals slept. The marsupial that does not sleep to reproduce reduces its sleep by 3 hours each night for weeks.
Death from exhaustion
The findings suggest that antechinus may have some way to thrive on less sleep during this time. Or perhaps they accept the downsides of staying awake to improve their chances of parenthood.
It is unclear what causes males to die after the breeding season. Researchers do not suspect that the only reason is loss of sleep. In part that's because the males seen sleeping the least were not the ones in the worst condition.
