The northern quoll (Dasyurus hallucatus), also known as the northern native cat, the North Australian native cat or the satanellus is a carnivorous marsupial native to Australia.
Taxonomy
The northern quoll is a member of the family Dasyuridae. There are three other quoll species found in Australia, and another two species found on the island of New Guinea, all of which are currently placed in the genus Dasyurus. The northern quoll was first described in 1842 by naturalist and author John Gould, who gave it the specific epithet hallucatus, indicating that it has a notable first digit. This species has sometimes been placed in a separate genus, Satanellus.
Four distinct morphological forms of the northern quoll were recognised in the 1920s, however more recent population genomic analysis has shown that these forms do not conform to the underlying genetic differentiation shown across the species distribution. Three broad population genomic clusters are present in the species, which broadly correspond to populations in the regions of Queensland, Northern Territory and Western Australia. Females are smaller than males, with adult females weighing between and adult males . Head and body length ranges from for adult males and for adult females. The tail length ranges between .
Northern quolls feed primarily on invertebrates, but also consume fleshy fruit (particularly figs), and a wide range of vertebrates, including small mammals, birds, lizards, snakes, and frogs. They also scavenge on roadkills, around campsites, and in garbage tins.
A remarkable feature of this species is that the males show complete die-off after mating, leaving the females to raise the young alone. Females have five to eight teats in a pouch, but apparently give birth to more than eight young which must wriggle their way to the pouch and compete for a teat to survive. In a study in Western Australia's Kimberley region, the testosterone levels of males peaked in July, and females gave birth in July or August.
In a study in Kakadu National Park, the Northern Territory, males live for about one year, while the maximum recorded for a wild female was about three years of age. Captive northern quolls are able to attain longer lifespans (M. Oakwood pers. obs.).
A 2001 study of male die-off found that during the mating season, males exhibited weight loss, fur loss, parasite infestation, increased testosterone levels and anaemia. During mating season, males adopted a roving strategy to try to access the maximum number of females. The females were widely spaced in savanna habitat so the males expended intense physical effort at that time, which was likely to be a major contributor to their physiological decline. In 2023, a study found that "reduced resting behaviour among males could explain the post-breeding death as the deterioration in appearance reflects that reported for sleep-deprived rodents."
Range and habitat
The northern quoll occurs from the Pilbara region of Western Australia across the Northern Territory to south east Queensland. There are several disjunct populations. This quoll species is most abundant in rocky ranges and open eucalypt forest. Analysis of occurrence records for the species shows that rocky areas are important for the species.
Northern quolls have declined substantially since European colonisation of Australia, with one study in the Northern Territory finding a roughly 60% contraction in their extent of occurrence.
Conservation status
right|thumb|1863 illustration by [[Elizabeth Gould (illustrator)|Elizabeth Gould]]
The northern quoll is currently classified as Endangered by the IUCN. Quolls are also susceptible to being run over on roads. Cane toads were originally introduced in Queensland, but have now occupied the Top End of the Northern Territory, including Kakadu National Park and the Darwin area, and entered the Kimberley region of Western Australia, where they are established around Kununurra and Lake Argyle.
Immediately after cane toad invasion of Kakadu, quolls became extinct at one study site and declined from 45 individuals to five at another site. The northern quoll may cease to exist in most areas in the Top End once the cane toad population completely overlaps the northern quoll's range. However, remnant populations of northern quolls still persist in Queensland where cane toads have been present for decades. These persisting Queensland quoll populations are naturally toad averse (as observed on remote cameras). One of the northern quoll populations studied in Kakadu during the recent cane toad invasion, had a few individuals survive the invasion. These individuals were, likely similar to the Queensland quolls, genetically averse to the toads. In 2003, to help protect northern quolls, numerous quolls were transferred to the toad-free English Company Islands (Astell and Pobassoo Islands), off the coast of Arnhem Land. Quolls thrived on these islands, with an estimated population of 2193 female northern quolls on Astell Island by 2014. In 2017, quolls from Astell Island were collected, trained via conditioned taste aversion to avoid attacking cane toads and reintroduced to Kakadu National Park. This reintroduction attempt saw the release both toad-trained (22) and toad-naive (9) northern quolls to an area of Kakadu that previous had quolls but where they had recently gone locally extinct due to the invasion of cane toads. Although the toad-trained quolls survived longer than those that received no toad training, ultimately this reintroduction population rapidly went extinct because of dingo predation. Subsequently, research comparing antipredator behaviours of quolls from Astell Island and mainland Queensland determined that quolls conserved on this island had lost their ability to recognise and avoid both dingo and cats, predators they have co-evolved with on mainland Australia for at least 3500 and 150 years respectively. This study suggests that animals conserved in complete isolation from predators can rapidly lose evolved antipredator behaviours, in this case in only 13 generations, when they are no longer maintained via natural selection.
Research has shown that the conservation of a single population, or even several populations, will not prevent the loss of substantial amounts of genomic variation and adaptive capacity across the species. The project received grant funding from the Australian Government's Environment Restoration Fund. in the Indigenous Kundjeyhmi, Kundedjnjenghmi and Mayali languages, djabbo in Kunwinjku, and in Wunambal. The Kunwinjku people of Western Arnhem Land (Northern Territory) regard djabbo as "good tucker".