Too much sex and lack of sleep lead male quolls to die

"Something is definitely causing their health to fail after just one season, and we think it is linked to sleep deprivation," Dr. Clemente added. "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."

He also claimed that the male quolls thin out, turn hostile, and exhibit a careless attitude toward their existence. They also relaxed their standards about their appearance to make the most of their one breeding season. They spend less time grooming, which causes their condition to deteriorate and parasite levels to rise noticeably.

Although the cause of death is unknown, the Northern Quoll is the largest mammal known to devote all of its energy to only one breeding season, a practice known as semelparity. Male and female differences in behavior, activity budgets, speeds, and trip distances were tracked, according to lead author and Ph.D. candidate Joshua Gaschk at UniSC.

"Two males, who we named Moimoi and Cayless, moved for 10.4 km (64.6 miles) and 9.4 km (5.8 miles) in one night, respectively. An equivalent human distance, based on average stride length, would be around 35-40km," said Gaschk.

The study was published in the Royal Society Publishing on February 1.

Study abstract:

Semelparity is a breeding strategy whereby an individual invests large amounts of resources into a single breeding season, leading to the death of the individual. Male northern quolls (Dasyurus hallucatus) are the largest known mammal to experience a post-breeding die-off; however, the cause of their death is unknown, dissimilar from causes in other semelparous dasyurids. To identify potential differences between male northern quolls that breed once, and females that can breed for up to four seasons, the behaviours, activity budgets, speeds and distances travelled were examined. Northern quolls were captured on Groote Eylandt off the coast of the Northern Territory, Australia, and were fitted with accelerometers. A machine learning algorithm (Self-organizing Map) was trained on more than 76 h of recorded footage of quoll behaviours and used to predict behaviours in 42 days of data from wild roaming quolls (7M : 6F). Male northern quolls were more active (male 1.27 g, s.d. = 0.41; female 1.18 g, s.d. = 0.36), spent more time walking (13.09% male: 8.93% female) and engaged in less lying/resting behaviour than female northern quolls (7.67% male: 23.65% female). Reduced resting behaviour among males could explain the post-breeding death as the deterioration in appearance reflects that reported for sleep-deprived rodents.