Quantity over quoll-ity: Endangered northern quoll males value sex more than sleep, with deadly consequences

Let this be a warning to you.

Northern quoll males may be so sex mad that their lustful all-nighters are causing them sleep deprivation and even death according to new research led by the University of the Sunshine Coast (UniSC).

Northern quolls are carnivorous marsupials about the size of a small cat. With several extant populations in the northern reaches of Western Australia, the Northern Territory and Queensland, the animals are endangered, with national numbers estimated to be around 100,000 individuals and rapidly declining.

A major factor in the marsupial’s decline has been the introduction of cane toads. Northern quolls feeding on or attacking the highly toxic invasive amphibians die, causing numbers to plummet.

Other risks to northern quoll numbers are predation by feral cats and habitat loss.

But the fiendish behaviour of the males of the species certainly isn’t helping keep numbers up.

“Male Northern quolls breed for one season, while females can breed for up to four,” says UniSC PhD candidate Joshua Gaschk, who is lead author of the recent study which was published in Royal Society Open Science.

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The team set out to find the physiological reason for male northern quolls’ shorter lifespan.

“Something is definitely causing their health to fail after just one season and we think it is linked to sleep deprivation,” says UniSC lecturer Dr Christofer Clemente. “The dangers of a lack of sleep are well documented in rodents, and many of the traits associated with sleep deprivation we see in male quolls, and not in females.”

Among these characteristics are weight loss, aggressive behaviour and reckless behaviour which threatens their survival.

Somewhat counterintuitively when it comes to attracting a mate, the male northern quolls spend so much time and energy in their sexual exploits that they “let themselves go” appearance-wise. Their condition declines as they spend less time grooming, also leading to an increase in parasites.

Gaschk says the researchers “found that male and female quoll behaviour differed significantly in many ways.”

Males spent less time sleeping and resting and also travelled longer distances than the females.

“Two males, who we named Moimoi and Cayless moved for 10.4km and 9.4 km in one night respectively. An equivalent human distance, based on average stride length, would be around 35-40km,” Gaschk explains.

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The researchers suggest that lack of rest means the males were less vigilant in finding food and avoiding predators.

“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,” Gaschk says. “They become easy prey, are unable to avoid vehicle collisions, or simply die from exhaustion.”

Northern quolls are the largest mammal known to invest all their energy into one breeding season – a strategy known as semelparity.

Researchers say the data on northern quolls may help understand the effect of sleep deprivation on other mammals, including those that display semelparity, in Australia and Papua New Guinea.

“We want to determine if sleep deprivation is experienced by other family members, such as opossums, antechinus (marsupial mice) and Tasmanian Devils,” Gaschk adds. “Virginian opossums (Didelphis virginiana  undergo a similar physiological change to other semelparous species but do not experience the die-off, while Tasmanian devils (Sacrophilus harrisii) experience a similar loss in condition and a reduced immunocompetence.”

“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.”

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