Endangered northern quolls could be shagging themselves to death, with the males apparently giving up sleep in favour of sexy time.
Researchers have delved into why males of the native species typically die after one mating season, while females reproduce for up to four.
The answer seems to be that their desire for sex overrides life-preserving rest.
"They cover large distances to mate as often as possible and it seems their drive is so strong they forgo sleeping to spend more time searching for females," says Dr Christofer Clemente, from the University of the Sunshine Coast.
They also let their looks go in the pursuit of sexual fulfilment.
Males will lose weight and with it physical condition, and their lack of interest in grooming probably explains why they carry more parasites.
If all that isn't enough, they also become more aggressive and seem reckless when it comes to their own survival.
Under a collaboration with the University of Queensland, researchers fitted wild roaming males and females with tracking devices on Groote Eylandt, off the Northern Territory coast.
The males spent far less time sleeping and resting than the females, and they walked more and travelled greater distances.
Two males covered about 10km each in a single night, which equates to 35 to 40km in human distance.
Males were also less vigilant when it came to looking for food and eating, avoiding predators and keeping themselves clean.
"Sleep deprivation, and associated symptoms for a prolonged duration would make recuperation impossible and could explain the causes of death recorded in the males after breeding season," says the study's lead author, University of the Sunshine Coast PhD candidate Joshua Gaschk.
"They become easy prey, are unable to avoid vehicle collisions, or simply die from exhaustion."
Researchers say more studies are needed on the effects of sleep deprivation in quolls and similar marsupial mammals, but the downsides of skipping sleep are well documented in rodents.
"We want to determine if sleep deprivation is experienced by other family members, such as opossums, antechinus and Tasmanian Devils," Mr Gaschk says.
"Virginian opossums undergo a similar physiological change to other semelparous species but do not experience the die-off, while Tasmanian devils experience a similar loss in condition and a reduced immuno-competence.
"If male northern quolls forgo sleep to the detriment of their survival, Northern quolls become an excellent model species for the effects of sleep deprivation on body function."
