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Red-tailed Phascogale - Phascogale calura
Red-tailed Phascogale - Phascogale calura

[Image: 640px-Phascogale_calura_close.jpg]

Scientific Classification:
Kingdom: Animalia 
Phylum: Chordata 
Class: Mammalia 
Order: Dasyuromorphia 
Family: Dasyuridae 
Genus: Phascogale
Species: Phascogale calura

Red-tailed phascogales forage both on the ground, and the trees, generally in occasions with stands of sheoak. They feed on a variety of invertebrates, particularly cockaroaches and beetles, but will also consume on small birds and mammals, such as the feral house mouse. They favour vegetation in climax communities, but they also occur in roadside remnants, oil mallee plantations and paddock trees in broadcare farming enviroments. How they adapt these is poorly understood and known, but it is for the sake for the conservation of the species. It averages 10cm in length, but can make leaps of 2m.

The brush-tailed phascogale species are distributed around the forested margins of the Australian mainland, whereas, the red-tailed phascogale had a historical distribution throughout the western and central desert regions of the continent (Van Dyck and Strahan 2008). However, since European settlement, the range of the red-tailed phascogale has declined dramatically, and they are now restricted to isolated patches of sheoak (Allocasurina) and Wandoo (Eucalyptus wandoo) forest in a small area of the wheatbelt in south-west Western Australia. As a consequence of this decline, their limited geographical range and their small overall population size of less than 10,000 individuals, red-tailed phascogales are listed by the IUCN as near threatened (Friend 2008).

[Image: 268px-Red-tailed_Wambenger_area.png]
Red-tailed phascogale range

Population dynamics
The post-European decline of red-tailed phascogales was presumably a consequence of clearing for agriculture, resulting in habitat loss and fragmentation, combined with predation by introduced predators and a fire regime characterised by more frequent burning which reduced cover and impacted on the availability of nesting hollows in senescent vegetation.
The current range of the red-tailed phascogale is characterised by the presence of Gastrolobium and Oxylobium understory vegetation which naturally contains the toxin monosodium fluoroacetate or 1080 poison, for which native fauna in the region has developed a resistance, but is lethal to domestic animals and introduced predators such as cats and foxes. This may have contributed to a refuge in this region for the red-tailed phascogale and other native species.
Conservation of the red-tailed phascogale will involve maintenance and monitoring of existing populations, some of which are already in protected areas, continued fire management and studying the impacts of changing predation pressure on phascogale populations. Understanding how phascogales respond to habitat modification and predator control programmes is important for the establishment of new secure populations.

[Image: Phascogale_calura_%28cropped%29.jpg]

The reproductive biology of the red-tailed phascogale is particularly interesting, as the males only live to breed during one season, surviving for only 11.5 months. The breeding season is highly synchronous, with all mating occurring during three weeks in July, after which time all males in the population die as a result of an increase in stress hormones which lead to gastro-intestinal ulceration and ultimately haemorrhage. This post-mating male die-off is characteristic of other dasyurid marsupials, most notably various species of antechinus. Females survive after mating to raise the young, and can reproduce for up to three years. As many as 13 young are born in early August; up to eight of these are raised in the pouch. Females have eight nipples and young remained attached to the nipple for about 45 days, so excess young don’t survive. Females may store sperm from multiple males until ovulation, so a single litter of pouch young can have multiple fathers.

Red-tailed phascogales nest in tree hollows, and like other small dasyurid marsupials, use daily torpor to conserve energy.Torpor is a controlled decrease in body temperature that reduces the metabolic rate and also the requirement for metabolic heat production. At an ambient temperature of 18°C, phascogales allow their body temperature to drop to as low as 23°C. Torpid phascogales assume a typical curled posture and are generally unresponsive. However, they can generate their own metabolic heat to re-warm to a normal body temperature of 34°C in a few minutes. The species is used as a model species in research. Studies have been conducted on behavioural thermoregulation and have indicated they bask to reduce their energy demands. Captive nutrition trials found red-tailed phascogales consume up to 39% of their body mass in food per day and their daily maintenance energy requirements are approximately 954 kJ. Like many other mammals their food intake during lactation changes to meet the increasing demands of the young Red-tailed phascogales also express T- cell receptors and co-receptors, Major Histocompatibility Complex, and interlukin-6 and its receptor
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Distribution and status of the red-tailed phascogale (Phascogale calura)
Quote:The red-tailed phascogale once extended widely across semiarid and arid Australia, but is now entirely confined to the southern wheatbelt of Western Australia, occupying less than 1% of its former range. Here it occurs in a portion of the Avon Wheatbelt, Jarrah Forest, Mallee, and Esperance Plains biogeographical regions. The species persists only in areas that have been extensively cleared for agriculture and where the remaining bushland is highly fragmented. It does not appear to extend into unfragmented habitat in either the Jarrah Forest to the west or Mallee region to the east. It occurs primarily in woodland habitat with old-growth hollow-producing eucalypts, primarily wandoo (Eucalyptus wandoo) or York Gum (E. loxophleba), but records from the periphery of its current range appear to come from a broader range of habitats, including shrublands and various mosaics of woodland, shrubland, and scrub-heath.

Key factors limiting persistence are likely to be fragmentation of habitat that is likely to greatly increase the risks associated with dispersal, a shortage of suitable nesting hollows in many vegetation associations, and predation by feral and domestic cats and by foxes. These factors, particularly fragmentation and lack of suitable nesting hollows, suggest that the species’ long-term persistence in areas beyond the wandoo belt is far from assured.
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