The taxonomy of A. longicaudus has been under debate for some time. It originally was classified under Phenacomys. The red tree vole was then placed in its own subgenus as Arborimus. Later this changed as further distinguishing information was gathered, indicated that the vole should belong to a separate new genus. These animals were once rare in museum collections, possibly because of their restricted habitat, but also because they are so small and occur so far up in the trees--making them somewhat unaccessible to study.
No studies have been done on communication in this species. However, other voles are known to use vocalizations, tactile communication, some visual signals, and scents. It is likely that A. longicaudus communicates with conspecifics in a similar fashion.
Communication Channels: visual ; tactile ; acoustic ; chemical
Perception Channels: visual ; tactile ; acoustic ; chemical
Logging has contributed to population declines and in some areas extinction. Due to this vole's high dependency upon a specific diet in primarily old-growth forests, they are vulnerable to fragmentation and loss of habitat. Arborimus longicaudus has come under protection via management strategies in the federal forests where it exists. This has been due to its lack of adaptability as well as its importance in the diet of endangered spotted owls.
US Federal List: no special status
CITES: no special status
IUCN Red List of Threatened Species: near threatened
Red tree voles hold no economic importance for humans.
Red tree voles hold no economic importance for humans.
Arborimus longicaudus is an important food source for the northern spotted owl, which is an important predator of old-growth forests.
Red tree voles are folivores with a highly specialized diet, feeding almost solely on Douglas fir needles. Red tree voles will use other conifer needles and bark in their diet, but in more minimal quantities. Studies done in labs have shown that they will eat other foods, but the voles will quickly die if deprived of their specialized diet. They obtain water from the foliage contents and also as dew on the needles. This may be important, as their habitat is limited to the moist, foggy forests where such condensation forms readily.
Plant Foods: leaves; wood, bark, or stems
Foraging Behavior: stores or caches food
Primary Diet: herbivore (Folivore )
Red tree voles, Arborimus longicaudus, are native to the Pacific Northwestern region of North America. Theya re found in the coniferous forests of Oregon and Norhtern California. They are present on the western side of the Cascade Mountains. The precise limits of the species distribution are unknown.
Biogeographic Regions: nearctic (Native )
Red tree voles typically inhabit old-growth forests, though they have been found in second-growth forests as well. They prefer the wet habitat provided in old-growth forests that contain mainly Douglas fir (Pseudotsuga menziesii). However, they are found in stands consisting of Sitka spruce (Picca sitchensis), grand fir (Abies grandis), and western hemlock (Tsuga heterophylla). These voles are arboreal in nature, building nests in various regions of the canopy, though one study showed greater accumulations of nests to be found in the lower canopy.
Habitat Regions: temperate ; terrestrial
Terrestrial Biomes: forest
Nothing is known about the lifespan of A. longicaudus, but few voles live more than 1 to 2 years.
Dorsal coloration of A. longicaudus is either a bright rusty-brown, or a uniform cinnamon. The venter is whitish. Tails are either black or brown. Juveniles are distinguished by duller coats, displaying more brown than red and having tails that are black. Red tree voles have soft long hair. Arborimus longicaudus shows sexual dimorphism in that females tend to be larger than males. Claws are replaced by nails on their first digit.
Mass for this species is reported at 25 to 50 g, with an average mass of 37 g. Length ranges between 166 and 187 mm, with an average of 170 mm.
This species is not sympatric with any other similar voles. Another member of the genus, Arborimus pomo is found in northern California, and is similar in size and color. However, the two species can be easily distinguished by range, as well as the fact that each has a different number of chromosomes.
Range mass: 25 to 50 g.
Average mass: 37 g.
Range length: 166 to 187 mm.
Average length: 170 mm.
Sexual Dimorphism: female larger
Other Physical Features: endothermic ; bilateral symmetry
Taking to the trees is thought to be one of the vole's adaptations to avoid terrestrial predators. However, these small rodents are subject to predation by raptors and a few climbing mammals such as fishers, martens, and raccoons. The most common predator of red tree voles is the northern spotted owl (Strix occidentalis), which is a federally listed threatened species. Red tree voles make up 50 % of this owl's diet.
Known Predators:
The reproductive system of this species has not been reported. Males and females do not live together, so it is unlikely that they are monogamous.
Females and males do not have much contact with each other. Males live in burrows in the ground during non-mating periods, whereas females keep to the nests in the trees. However, males will climb the trees, building smaller temporary nests, during mating season. This allows them to breed with the females.
Most breeding occurs from February to September, but these animals have been reported to breed throughout the year. Litters consist of one to three young. The estrous cycle lasts on average 5.9 days. The length of gestation is variable, lasting from 27 to 48 days. The gestation is longer in lactating females, although the mechanism for this delay has not been reported. This species is known to undergo postpartum estrous.
At birth, young weigh 2 to 3 g. Growth is slow compared to other species of voles. This slow growth and development may be an adaptation of this species to the poor food quality of pine needles.
The young are weaned at 30 to 35 days of age.
Breeding interval: These animals are reportedly capable of producing about three litters per year.
Breeding season: Breeding is year-round, but most occurs between February and September.
Range number of offspring: 1 to 3.
Range gestation period: 27 to 48 days.
Average gestation period: 28 days.
Range weaning age: 30 to 35 days.
Key Reproductive Features: iteroparous ; year-round breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; fertilization ; viviparous
The female red tree vole takes care of the young. Males are only present during the breeding season. The young of this species are altricial. The females cares for the young until they are slightly more than 36 days old.
Parental Investment: no parental involvement; altricial ; pre-fertilization (Protecting: Female); pre-hatching/birth (Provisioning: Female, Protecting: Female); pre-weaning/fledging (Provisioning: Female, Protecting: Female); pre-independence (Provisioning, Protecting: Female)
The red tree vole (Arborimus longicaudus) is a rodent of the Pacific Northwest, found in the US states of Oregon and California. They were formerly known as Phenacomys longicaudus and have also been called the red tree mouse.
The red tree vole is a rodent in the family Cricetidae.[2] It is found only in coastal forests of Oregon and northern California. They exclusively eat the needles of conifers, primarily Douglas-fir (Pseudotsuga menziesii), though they have occasionally been reported to eat the needles of Sitka spruce (Picea sitchensis).[3]
Red tree voles are about 6-8 in long, including the tail.[4] When they are young, they exhibit a dull brown coat and develop a more reddish color with age. They are nocturnal and very difficult to see, but they can be detected by finding piles or wads of these resin ducts on the ground.[5]
Red tree voles live almost exclusively in Douglas-fir trees, though they have occasionally been found in Sitka spruce and western hemlock (Tsuga heterophylla). They sometimes spend their lives in just one tree, and in very large trees with complex structure many generations can live in different parts of the same tree.[4] Red tree voles have been shown to have a home-range averaging around 800 m2, though this area is somewhat smaller in old forest (<80 years) and larger in young forest. Within this home-range they can have nests in up to 6 different trees, although 2 nests are average for females and 3 nests are average for males.[6]
When eating Douglas-fir needles, they carefully remove the fine resin ducts (which resemble coarse, straight hairs) along each edge of the needle, which then become a major component of their nests (see image below). As well as these resin ducts, their nests are composed of small Douglas-fir cuttings and their own scat. These nests are often built on or in large or epicormic branches, broken tops, cavities and split trunks, and are always within the live crown.[7]
Both sexes of red tree vole build nests, though the maternal nests are considerably larger.[7]
Red tree voles have small litters consisting of 1 to 4 offspring and a long gestation period of 28 days compared to other Microtines. Juveniles depend on their mothers for 47 to 60 days before complete independence. Females exhibit post-partum mating where they can breed within a few days of giving birth and it is common to find two separate litters living in the same nest.[8] During peak breeding periods (winter and spring), males disperse and travel longer distances from home in search for females that are sexually receptive. Females tend to stay closer to their nests, therefore having smaller home ranges.[9]
The northern spotted owl is one of the red tree voles' primary predators. Recent studies show that short-tailed weasels are also another primary predator of the red tree vole. Females are easier to detect by predators due to their maternal nests. The time they spend outside of their nests searching for food to bring back for their young also puts them at a higher risk of predation.[10]
Their habitats in old forests have become a concern for the species. Logging and habitat fragmentation has determined their status as vulnerable on the list of sensitive species on the Oregon coast.[10] They are vulnerable to timber harvest due to their arboreal lifestyle and their low reproductive rates contribute to the concern of the species becoming further threatened.[8] They are an important food source for the threatened Northern Spotted Owl and have been listed as a "survey and manage species" under the Northwest Forest Plan (NWFP) in order to help manage the area's ecosystem.[11]
The red tree vole (Arborimus longicaudus) is a rodent of the Pacific Northwest, found in the US states of Oregon and California. They were formerly known as Phenacomys longicaudus and have also been called the red tree mouse.
