Rattus leucopus

719.

Cape York Rat

Rattus leucopus

French: Rat de Cape York / German: Kap-York-Ratte / Spanish: Rata de York

Other common names: Mottle-tailed Rat, Mottle-tailed Cape York Rat, Spiny-furred Rat

Taxonomy. Acanthomys leucopus Gray, 1867,

“North Australia [Queensland]; Cape York.”

Rattus leucopus is basal to the rest of the Australian species within Rattus, which are altogether sister to the Recent New Guinea species. Taxonomic revision is needed for R. leucopus and all other species in New Guinea, and R. leucopus might represent multiple species. Five subspecies recognized.

Subspecies and Distribution.

R.l.leucopusGray,1867—NCapeYork,Queensland, Australia.

R.l.cooktownensisTate,1951—SECapeYork,Queensland,Australia.

R.l.doboduraeTroughton,1946—SENewGuinea.

R. l. ratticolorJentink, 1908 — SW New Guinea, probably including the Aru I. R. l. ingens Peters & Doria, 1880 — SC New Guinea.

Descriptive notes. Head-body 135-210 mm,tail 140-210 mm, ear 18-24 mm, hindfoot 33-40 mm; weight 90-205 g. The Cape York Rat is mediumto large-sized and relatively distinctive, with coarseand spiny pelage and grayish or translucent-based yellowish white spines, dark brown to black guard hairs, and light gray underfur dorsally and ventrally. Dorsum is grizzled and ranges from blackish brown (subspecies leucopus, cooktownensis, and dobodurae) to golden yellowish brown (leucopus and cooktownensis), some with more rust (ringens and ratticolor) or yellowish rust (dobodurae) mixed in, and being more yellowish or lighter on sides and neck and having cinnamon brown-tipped hairs. Some specimens have distinctive black eye-ring (only in cooktownensis); venter is white (leucopus), cream (dobodurae, ringens, ratticolor), or gray (cooktownensis), always with buff tinge. Some specimens have reddish brown patch on chest. Juvenile pelage is generally softer and darker, without well-developed spines. Feet are dull white dorsally and unpigmented ventrally; hindfeet are relatively broad. Ears are dull brown and sparsely haired;vibrissae are relatively short and dark. Tail is ¢.100% of head-body length, slender, and naked, ranging from dull brown throughout (always in leucopus, rarely in dobodurae), dull brown with whitish mottling throughout (always in cooktownensis, rarely in ringens and ratticolor), or dull brown with white tip or ring on middle oftail (most common in dobodurae, ringens, and ratticolor). Subspecies cooktownensis is similar to the Australian Bush Rat (R. fuscipes coracius), which is sympatric, and can be distinguished by presence of black eye-ring. Subspecies cooktownensis also has apungent smell, which can also help with identification. Skull is elongated, with long rostrum and narrow cranium. Subspecies ratticolor is the largest subspecies and similar to ringensin color. Various endoparasites (one acanthocephalan, five cestodes, one trematode, and 21 nematodes) have been recorded from the Cape York Rat. There are three pairs of mammae: one pectoral and two inguinal (some Australian specimens have a fourth pair pectorally). Diploid numberis 2n = 34.

Habitat. Tropical moist forest, gallery forest, rural gardens, and secondary forest from sea level to elevations of ¢.1200 m. In forest fragments, subspecies cooktownensis is the most common or only species of Rattus in its distribution, but in relatively disturbed areas, the Australian Bush Rat subspecies coracius is dominant.

Food and Feeding. The Cape York Rat is largely omnivorous and primarily eats nuts, fruits, and insects. Fungi also make up a major part ofits diet, although insects seem to be the preferred food type. Food is found by foraging at night through leaflitter.

Breeding. Cape York Rats reproduce year-round, with increases in wet season and decreases in late dry season; male reproductive condition peaks in December with high fruit availability. Gestation lasts 21-24 days. Litters have 2-5 young, which is somewhat low for the genus, and females may have up to 3 litters/year depending on how favorable seasonal climate is. Young develop relatively slowly compared with other Australian species of Rattus. They open their eyes at c.22 days and are weaned at ¢.25 days. They reach sexual maturity at ¢.3 months, and females usually have their first litter when they are at least four months old.

Activity patterns. The Cape York Rat is nocturnal, foraging and moving around at night in leaf litter and other debris. It is terrestrial, nesting communally in some burrows, although not always. Nests are generally located in burrows hidden underleaflitter on the forest floor, but holes in rotting logs and at bases of trees are also used for nests. Nests generally have several entrances and interconnected chambers. Several adults and juveniles can nest in the same burrows, and individuals might use multiple burrows.

Movements, Home range and Social organization. Densities of Cape York Rats are generally low in the northern subspecies but can be high for other subspecies. Populations fluctuate relative to food availability, although populations are relatively stable and do not fluctuate much because food sources are relatively stable year-round in Australia. In one study, vocalizations tended to be expressed in pulses at low frequency.

Status and Conservation. Classified as Least Concern on The IUCN Red List. The Cape York Rat has a wide distribution and large overall population, is found in many protected areas, and does not appear to face any major conservation threats. Populations are generally stable in Australia, but more research is needed to assesspopulation status of New Guinean.

Bibliography. Aplin, Burnett & Winter (2016), Dwyer (1984), Flannery (1995a, 1995b), Leung (1999), Menkhorst & Knight (2010), Musser & Carleton (2005), Robins et al. (2014), Rowe et al. (2011), Smales & Spratt (2004), Taylor Calaby & Smith (1990), Taylor, Calaby & Van Deusen (1982), Van Dyck& Strahan (2008), Yosida (1973), Watts (1980), Winter et al. (1984).