Dasyurus viverrinus (Shaw, 1800)

Russell A. Mittermeier & Don E. Wilson, 2015, Dasyuridae, Handbook of the Mammals of the World – Volume 5 Monotremes and Marsupials, Barcelona: Lynx Edicions, pp. 232-348 : 305

24.

Eastern Quoll

Dasyurus viverrinus

French: Quoll viverrin / German: Tipfelbeutelmarder / Spanish: Dasiuro oriental

Other common names: Eastern Native Cat

Taxonomy. Didelphis viverrinus Shaw, 1800 ,

Sydney, New South Wales, Australia.

In recent genetic (mtDNA and nDNA) phylogenies, the quoll group (D. geoffrou, D. hallucatus , D. maculatus , and D. viverrinus) has been found to be monophyletic; the sister taxon to this group is evidently the Tasmanian Devil ( Sarcophilus harrisi). D. viverrinus was found to be clearly genetically divergent from all other quolls, with strong support for its monophyly with respect to congeners; however,its sister relationship with the D. geoffroii / D. spartacus /D. albopunctatus clade or the D. maculatus clade was uncertain. Monotypic.

Distribution. Now present only in Tasmania and Bruny I.

Descriptive notes. Head-body 32-45 cm (males) and 28-40 cm (females), tail 20-28 cm (males) and 17-24 cm (females); weight 0.9-1.9 kg (males) and 0.7-1.1 kg (females). There is marked sexual dimorphism for size. The Eastern Quoll is distinguished from the Spotted-tailed Quoll ( D. maculatus ) by its smaller size, presence of only four toes on hindfoot, and absence of spots on tail. Two distinct color morphs exist: pale fawn to gray and, less commonly,jet black.

Habitat. Open forest and woodland, open grasslands, and alpine heaths from sea level to elevations of 1000 m. Although it occurs throughout Tasmania, the Eastern Quoll is mostly found in drier eastern regions, reaching its highest densities where lush foraging pasture abuts forests, in which they den.

Food and Feeding. The Eastern Quoll eats insects and small vertebrates, including skinks, small snakes, birds, and small mammals. In farmland, insects evidently comprise a large part of the diet, particularly the corbie grub, a common pasture pest. Soft fruits, such as blackberries, are commonly eaten by Eastern Quolls. They also eat grass, although its ingestion may be incidental. In alpine areas, insects are more limited, and the diet switches to mostly birds and mammals. The Eastern Quoll readily scavenges and may have a commensal relationship with Tasmanian Devils, which rip open large, tough carcasses for them. One study examined diets of Eastern Quolls from one locality in southern Tasmania, near the Huon River c.40 km south of Hobart. The area included two small copses of remnant dry sclerophyll forest surrounded by 100 ha of cultivated pasture. Sixty-four fecal samples from 41 Eastern Quolls were collected during three intervals across eight months. Insects comprised the bulk of the diet and occurred in 97% offeces. Remains of birds (the Superb Fairy-wren, Malurus cyaneus) and small mammals (the House Mouse, Mus musculus ) were found in only 17% offeces. All feces contained similar amounts of plant material.

Breeding Mating of the Eastern Quoll occurs from mid-May until early June. After gestation of c¢.3 weeks, females give birth to as many as 30 young, of which only six can attach to the six available teats. Six millimeters long at birth, young remain fixed to the teat until mid-August when the mother leaves them in a grass-lined den. The mother carries them on her back if she moves from one den to another, but when she goes out to forage, young are left in the den. Juveniles teach themselves to hunt, becoming independent by the end of October. They engage in vigorous play and may be seen at night in pairs or groups chasing each other’s tail. They become sexually mature by the following breeding season. Individuals with either black or fawn coat color occur in the same litter, independentof their sex or color of their parents. One study of growth of captive young Eastern Quolls found that they were able to detach from the teat by c.65 days of age and their eyes were open by ¢.80 days. Weaning commenced at ¢.102 days of age and coincided with eruption of first molar teeth. Total independence, determined by cessation oflactation in the mother, occurred as early as 142 days (in litters with one offspring) or as late as 200 days (largerlitters). Another study of Eastern Quolls in captivity found that gestation was 20-24 days. If the first litter was lost early in lactation, females might return to estrus. The Eastern Quoll was therefore considered polyestrous. A study on energetics found that digestible energy intake of lactating Eastern Quolls was nearly double that of non-lactating quolls. Researchers proposed that with such high-energy demands during lactation,it is unlikely that a completelitter of six could be successfully reared unless their prey was abundant.

Activity patterns. Eastern Quolls emerge at dusk and hunt at night; they move easily over snow. They enter torpor occasionally in extreme weather conditions.

Movements, Home range and Social organization. Eastern Quolls are solitary foragers and typically avoid each other, although home ranges overlap extensively. Males have larger home ranges (44 ha) than females (35 ha). Males may travel more than 1 km in a night; females often move only a few hundred meters around their dens. Den sites include underground burrows, hollow logs, rock piles, and hay sheds; each den may have several chambers. Females regularly share dens with males or other females, but males will mostly den alone. Both sexes use multiple dens, except females with young. Social interactions among Eastern Quolls increase during the breeding season when fights between males become more frequent.

Status and Conservation. Classified as Near Threatened on The IUCN Red List. Although the Eastern Quoll has undergone massive declines in its historical distribution (atleast 50%), it is considered to be reasonably common and widespread in most habitat types on Tasmania, and it is not thought to be suffering significant decline now. Eastern Quolls were formerly distributed in eastern New South Wales, Victoria, and south-eastern South Australia. Nevertheless, they disappeared from mainland Australia between 1900 and 1963; their extinction followed the arrival of Red Fox (Vulpes vulpes). Recent introduction of the Red Fox in Tasmania has the potential to be a major threat to Eastern Quolls in the near future. If control measures for Red Fox are not successful on Tasmania, Eastern Quolls may face a significant decline in the next ten years (but unlikely to be as great as 30%), thus making it close to qualifying for IUCN status as Vulnerable under criterion A. In a recent study, combined evidence from annual spotlight surveys, trapping surveys targeting the Eastern Quoll, and a variety of non-targeted trapping fauna surveys suggests that Eastern Quolls are undergoing severe and rapid decline, with subsequent spotlight surveys giving no signs of recovery. The recent decline may simply represent natural population fluctuations from which the Eastern Quoll is likely to recover without intervention. Alternatively, it may represent a shift to an unstable state, and at worst, a trajectory toward extinction. Authors of this research noted that the observed reduction of more than 50% over ten years is consistent with IUCN’scriterion for listing the species as Endangered, although it is currently classified as Near Threatened. Given its status as a top-order predator, ensuring conservation of the Eastern Quoll on Tasmania must be considered a high priority. This is because persistence of several mammal species in Tasmania after they were expunged from the mainland may be largely attributable to persistence of a relatively intact guild of marsupial carnivores, including the Tasmanian Devil, the Spotted-tailed Quoll ( D. maculatus ), and the Eastern Quoll, in addition to the absence or low density of introduced eutherian carnivores such as the Red Fox. In short, top-down regulation of ecosystem processes by Tasmania's marsupial carnivores may have contributed to the retention of biodiversity on the island. Such interactions have not yet been tested in Tasmania, but researchers working on ecosystems across the planet have documented similar trophic interactions and subsequent extinction of prey species following the removal of high-order carnivores. Mortality of young Eastern Quolls while in the pouch and den is low; thus, large numbers ofjuveniles enter the population in November. Death and dispersal of juvenile and adult Eastern Quolls over summer and autumn reduces the population by the following breeding season. Males and females can breed for several years, but the majority of breeding adults in a given year are those born during the previous season. Eastern Quolls are susceptible to road mortality, which can cause major declines of local populations. Juveniles are vulnerable to predation by domestic and feral cats and Red Fox; together, these two introduced species pose a major risk of extinction to Eastern Quolls in Tasmania.

Bibliography. Blackhall (1980), Fancourt et al. (2013), Firestone (2000), Fletcher (1985), Godsell (1982), Green et al. (1997), Hill & Hill (1955), Jones (2008a), Jones, Smith & Jones (2004), McKnight (2008a), Merchant et al. (1984).

Figures

On following pages: 2. Crest-tailed Mulgara (Dasycercus cristicauda); 3. Kowari (Dasyuroides byrnei); 4. Kaluta (Dasykaluta rosamondae); 5. Dibbler (Parantechinus apicalis); 6. Woolley's Three-striped Dasyure (Myoictis leucura); 7. Miller's Three-striped Dasyure (Myoictis melas); 8. Wallace's Three-striped Dasyure (Myoictis wallacii); 9. Tate's Three-striped Dasyure (Myoictis wavicus); 10. Sandstone Pseudantechinus (Pseudantechinus bilarni); 11. Fat-tailed Pseudantechinus (Pseudantechinus macdonnellensis); 12. Carpentarian Pseudantechinus (Pseudantechinus mimulus); 13. Ningbing Pseudantechinus (Pseudantechinus ningbing); 14. Rory’s Pseudantechinus (Pseudantechinus roryi); 15. Woolley's Pseudantechinus (Pseudantechinus woolleyae); 16. Speckled Dasyure (Neophascogale lorentzii); 17. Red-bellied Phascogale (Phascolosorex doriae); 18. Narrow-striped Dasyure (Phascolosorex dorsalis).

Distribution. Now present only in Tasmania and Bruny I.