Sorex gaspensis
Gaspé shrew

The geographic range of the Gaspé shrew covers select mountainous regions of eastern North America. In 1974, fifty years after it was first described (Anthony and Goodwin 1924), a relict population of Sorex gaspensis was discovered inhabiting Cape Breton Highland National Park, Nova Scotia. Today populations exist in three disjunct locations in Canada: 1) the Gaspé peninsula of southeastern Québec, 2) north central and western New Brunswick, and 3) Cape Breton Island, Nova Scotia. (Kirkland, 1999; Roscoe and Majka, 1976)

What is known about S. gaspensis habitat preferences has been learned from limited trapping occurrences throughout its range. These shrews are found in boreal spruce or mixed deciduous forests. They occur in areas of leaf-litter, or moss-covered, rocky terrain. They have been trapped at elevations from 290 to 490 m.

S. gaspensis is trapped in areas with habitat similar to the habitat of water shrews, S. palustris. Trap sites of the Gaspé shrew are often associated with small brooks or tributaries. However, the habitat of the Gaspé shrew is more often compared to that of the rock shrew, S. dispar. Both S. gaspensis and S. dispar fill the niche of living in and among rocks in higher elevations, but the two are not sympatric. (Kirkland, 1981; Kirkland, 1999; Roscoe and Majka, 1976)

Gaspé shrews are slate-gray in color with the dorsal side slightly darker than the ventral side. There is no known seasonal variation in pelage color. The tail is not bi-colored and is relatively long, measuring an average of 49.7 mm. This length is between 80 and 90 per cent of the head-body length. (Kirkland, 1981)

S. gaspensis is characterized as small and slender, most notably in the skull. The ‘delicately constructed’ skull has a very narrow rostrum. It is characterized as ‘non-angular’ and very depressed. Weights recorded for trapped specimens range from 2.2 to 4.3 g. (Kirkland and Van Deusen, 1979)

The external characteristics of S. gaspensis should easily distinguish it from all other sympatric Soricidae. (Kirkland, 1981)

Although the two look very similar, S. gaspensis is generally distinguished from its closest relative, S. dispar, by its overall smaller size, slightly paler coloration, weaker dentition, and the proportionally larger hind foot to body size. As well, the range of possible condylobassal (15.35–16.35 mm; n=18) and the molariform tooth row (3.40-3.65mm; n=18) lengths only rarely overlap for the two species. S. dispar has lengths greater than those given above. (French and Kirkland Jr., 1983; Kirkland, 1981)

The life span of S. gaspensis is unknown, however, species from the genus Sorex typically live between one and two years. (Nowak and Paradiso, 1983)

The behavior of S. gaspensis is not known. However species of the genus Sorex tend to be solitary and highly aggressive toward one another. It is likely that Gaspe shrews are like their congeners in this respect. (Nowak and Paradiso, 1983)

Memebers of the genus Sorex are often active both day and night. Although they may sleep very deeply, when they are awake, they are very quick and active, darting from here to there. Home ranges for these animals range from 532 to 5,261 square meters. and may vary seasonally. (Nowak and Paradiso, 1983)

Home Range

The home range of S. gaspensis is not known.

Communication in this species has not been described, as captures tend to be made in pit-fall traps. However, it is likely that, as in most mammals, there is some tactile, accoustic,and chemical communication. Most shrews don't seem to have really well developed eyes, so it seems unlikely that visual communication, especially over distance, plays an important role in this species. (Kirkland, 1999)

The stomach contents of 62 Gaspé shrews trapped during the summer of 1980 were examined to better understand the composition of their diet. Insect larvae and spiders were found to make up 25 percent and 23 percent of the stomach contents, respectively. Spiders were recognized as the single most important arthropod order in the diet of these animals, because of the myriad orders from which the other insect larvae came. Beetles (Coleoptera) and flies (Diptera) were the next most abundant specimens found at 10.6 percent and 11.8 percent in the stomach contents respectively. Overall, adult insencts comprized half of the stomach contents. Although not common, earthworms, and snails, and slugs were also found in the stomachs of S. gaspensis. (Whitaker and French, 1984)

Plant matter was found in two specimens of S. gaspensis trapped during the summer of 1953. (Hamilton and Hamilton III, 1954)

It is believed that a great deal of hunting takes place in crevices and fissures of the rocky habitat these shrews occupy. Hence, with its small size, slender body, narrow rostrum and procumbent incisors, S. gaspensis is well adapted for its feeding ecology. (Hamilton and Hamilton III, 1954; Kirkland, 1999)

The predators of these animals have not been described. However, as with most small mammals, they probably are victims of predation by sympatric canids, felids, mustelids, hawks, and owls. It is not known if the rapid, darting movement common in the genus Sorex is an adaptation to finding food rapidly, or making capture by predators more difficult.

It is difficult to speculate on the ecological importance of these shrews. The species is distributed over a very small area, and densities do not appear to be very high. However, it is likely that these animals affect populations of the species upon which they prey (at least in a very local way). They may also have some impact on predator populations, although it is unlikey that any predator species would be able to rely heavily upon these animals.

Gaspé shrews have no known negative effects on humans.

There is no known positive impact of these animals on humans.

Due to extremely low trapping success until 1980, Gaspé shrews were formerly considered one of the rarest mammals in North America. Currently, S. gaspensis is listed as a species of special concern in Canada by the Committee on the Status of Endangered Wildlife in Canada.

The Atlantic Canada Conservation Data Center (AC CDC) has given S. gaspensis the following species rarity ranks following the standardized system of the Nature Conservancy and United States Natural Heritage Programs: Global rank of G3, species rarity rank in New Brunswick of S1 and species rarity rank in Nova Scotia of S2.

G3 is defined as, "Either very rare and local throughout its range (21-100 occurrences or less than 10,000 individuals) or locally in a restricted range or vulnerable to extinction from other factors."

S1 is defined as, "Extremely rare throughout its range in the province (typically 5 or fewer occurrences or very few individuals). May be especially vulnerable to extirpation."

S2 is defined as, "Rare throughout its range in the province (6 to 20 occurrences or few remaining individuals). May be vulnerable to extirpation due to rarity or other factors." ("Atlantic Canada Conservation Data Centre", 2003)

Due to the Wisconsin Glaciation and current waterways preventing any northern movement, S. gaspensis is one of only two boreal mammals whose range lies completely south of the St. Lawrence river. (Kirkland and Van Deusen, 1979)