Scapanus townsend, Bachman, 1839
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publication ID |
https://doi.org/ 10.5281/zenodo.6678191 |
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DOI |
https://doi.org/10.5281/zenodo.6671936 |
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persistent identifier |
https://treatment.plazi.org/id/0380B547-B65B-FF8A-9FA0-F5ACFECEC836 |
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treatment provided by |
Valdenar |
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scientific name |
Scapanus townsend |
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Townsend’s Mole
French: Taupe de Townsend / German: Townsend-Maulwurf / Spanish: Topo de Townsend
Taxonomy. Scalops townsendii Bachman, 1839 ,
vicinity of Vancouver, Clark County, Washington, USA.
Scapanus townsendii View in CoL is a sister species to S. orarius View in CoL . Two subspecies recognized.
Subspecies and Distribution.
S. t. olympicus M. L. Johnson & Yates, 1980
— known only from elevations above 1000 m in Olympic National Park, NW Washington (USA). View Figure
Descriptive notes. Head-body ¢.161-186 mm, tail 34-51 mm, hindfoot 23-31 mm; weight 64-171 g. Males are an average of 22% heavier than females. Townsend’s Mole is by far the largest species of Scapanus , with naked snout and shortesttail relative to head-body length (less than 25%). Furis gray to black,lighter in summer, and darker in winter. Aberrant color was found in ¢.30% of skins; uncharacteristic individuals usually have one to several spots of different size and color (white to brown); exceptionally, individuals are mottled, white with yellow shading, or pure albinos. Females have four pairs of nipples. Skull is oftypical mole proportions, rather compressed and with large orbits. Rostrum is moderately broad. Zygomatic arches are complete, but jugal bone is missing. Mandible shows no peculiarities. Dental formula is I 3/3, C 1/1, P 4/4,M 3/3 (x2) = 44. I' is large and flattened, and premolars are single rooted. Karyotype is 2n = 34.
Habitat. Meadows, pastures, farmland, lawns, and river floodplains, preferring medium-textured silt loam soil with good humus content, and less frequently prairies, shrublands, and coniferous forests, from sea level to elevations of 1677 m in the Cascade Mountains. Townsend’s Moles rarely occur in gravelly soils.
Food and Feeding. Diet of Townsend’s Mole mainly contains earthworms and insects, which are supplemented with centipedes (Chilopoda), slugs, snails, spiders, small mammals, and plants. In various studies, stomach content contained 54-9-76-1% earthworms and 6-8-39-2% vegetable matter. Townsend's Moles prey on all developmental stages of various insects: flies ( Diptera ), butterflies and moths ( Lepidoptera ), beetles ( Coleoptera ), hymenopterans (Hymenoptera), and crickets and grasshoppers ( Orthoptera ). Vegetation is represented in the diet by soft wheat, sweet corn, bulbs, and grass roots. Some authors claim that Townsend’s Moles eat succulent vegetation only when deprived of water. Caged young were maintained on a diet of warm cow milk and afterward earthworms and ground beef. Individuals fed beef require drinking water. Stomachs contained an average of 3-6 g of food (maximum of 9-8 g); average daily ration was 57 g.
Breeding. Breeding season of Townsend’s Mole starts in November, and females are pregnant between late February and early April. Gestation presumably lasts 4-6 weeks, and one litter is produced annually. Mean number of embryos (2-7, range 1-6) is basically the same as number of young (mean 2-9, range 1-4). Nursery nests are usually close to the ground’s surface where they can be warmed by the sun. Additional warmth comes from decaying plant material in the core of the nest. A female can excavate a nest cavity in five days and deposits soil in a single nest mound 75-125 cm in diameter. Nursing nests can be reused during the next breeding season. Neonates are blind, naked, and weigh c.5 g each. Fur starts growing at 15-20 days old and is fully developed by 30 days old when young weigh 60-80 g. About 68% of young survive to disperse at 30-36 days old, and they breed in winter following their birth.
Activity patterns. Townsend’s Mole is fossorial and digs extensive underground galleries. Diameter of tunnels is ¢.5 cm. Shallow surface tunnels (5.1-15.2 cm deep) serve for hunting and are frequently located under objects lying flat on the ground (e.g. boards or logs). Permanent tunnels are usually 15-20 cm underground and can occasionally descend 1-3 m; they are mainly used during dry seasons. Deep tunnels under obstacles can serve as community “highways” for more than one individual. Unearthed soil is pushed onto the surface, resulting molehills ¢.17 cm high and 43 cm in diameter. There can be as many as 805 molehills/ha, and one individual produced 302 mounds in 77 days. Spherical nesting cavities are 7.6-50.8 cm (usually 15.2-20.3 cm) underground, typically in areas oflittle disturbance. The cavity has mean volume ¢.1639 cm” and 3-11 entrances. Inner lining of a nest consists offine dry grass, and outer lining is grass, leaves, and mosses, frequently still green and wet. Young Townsend's Moles are more active aboveground, particularly in April-July. They disperse at night up to 856 m either through communal tunnels or aboveground. Townsend’s Mole swims well and can move through flooded tunnels.
Movements, Home range and Social organization. Most Townsend's Moles (90% males and 84% of females) traveled less than 300 m during postnatal dispersal. Females moved slightly further from the nest (mean 181 m, maximum 856 m) than males (166 m and 722 m, respectively). Within a home range, largest distance between two points was 116 m. Townsend’s Moles tend to travel furtherif they live in poor habitat. Several individuals displaced by rising water moved 113-149 m from their nests, and all returned after water receded. Densities are 0-42—-12-4 ind/ha. Townsend’s Moleis solitary and territorial. Intraspecific encounters are frequently antagonistic.
Status and Conservation. Classified as Least Concern on The IUCN Red List. The Canadian population of Townsend’s Mole occupies only 13 km? has only ¢.450 mature individuals, and is classified as Endangered. Numbers of Townsend’s Moles in the Pacific Northwest presumably increased in the past several centuries because of expansion of farmlands, but this was partly counterbalance by persecution and control measures. In the past, Townsend’s Moles were trapped for skins. Severe flooding can significantly reduce populations of Townsend’s Moles.
Bibliography. British Columbia Ministry of Environment (2014), Carraway & Verts (1991b), Carraway et al. (1993), COSEWIC (2003), Giger (1965, 1973), Kuhn et al. (1966), Maser et al. (1981), Moore (1933), Verts & Carraway (1988).
No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.
