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King Giant Rat

Uromys rex

French: Uromys roi / German: Konigsriesenratte / Spanish: Rata gigante real

Other common names: King Rat, King Uromys

Taxonomy. Mus rex Thomas, 1888,

“Aola, Guadacanar [= Guadalcanal Island] Solomon Islands.”

Within Uromys, U. rexis included in subgenus Cyromys along with the other two Guadalcanal species, namely U. imperator and U. porculus. Monotypic.

Distribution. Guadalcanal I, Solomon Is.

Descriptive notes. Head-body 257-290 mm, tail 232-296 mm, ear 16-20 mm, hindfoot 50-55 mm; weight 420 g. The

King Giant Rat is a mid-sized to large species of Uromys similar to the Emperor Giant Rat (U. imperator), from which it is distinguished by its longer, roughertail with larger scales and its smaller size. Pelage is short and woolly to the touch, but looks wiry. Dorsal pelage is dark grizzled ash gray, and ventral pelage is white. Feet are broad and naked. Ears are short and silvery pink; vibrissae are long, and black or white. Tail is relatively long (90-105% of head-body length) and blackish brown. Skull is broad with a broad and deep rostrum, in contrast to the Emperor Giant Rat. There are two pairs of mammae, both inguinal.

Habitat. Primary tropical moist forest such as relict patches of native forest, at elevations of 20-600 m.

Food and Feeding. No information.

Breeding. No information.

Activity patterns. The King Giant Rat is arboreal, the only certain arboreal species of Uromys on Guadalcanal. It has been encountered around dusk.

Movements, Home range and Social organization. No information.

Status and Conservation. Classified as Endangered on The IUCN Red List. The King Giant Rat is known from very few specimens and is considered rare and declining throughout its range. It is threatened by habitat loss from agricultural expansion and logging. This species is apparently the most common of the three Guadalcanal Uromys species, and it was able to survive perhaps because ofits arboreal habits, while the Emperor Giant Rat may have become extinct, or at least highly diminished, because of its probable terrestrial habits. Further research is needed in order fully to understand this species’ natural history and evolution, and any threats facing it.

Bibliography. Bryant et al. (2011), Flannery (1995a), Groves & Flannery (1994), Helgen, Leary & Wright (2016c¢), Musser & Carleton (2005), Steppan & Schenk (2017).