Trowbridge's Shrew (Sorex trowbridgii) lives in pacific coastal forests across North America. It feeds on insects and seeds. Its conservation status is Least Concern.
Fascinating facts about the Trowbridge's Shrew
- When a Trowbridge's shrew hits breeding age it adds about 1.2 g to its body, swelling from a feather-light 3.8 g (0.13 oz) to about 5 g (0.18 oz). This jump in mass fuels the rapid growth of male testes and the widening of female uterine horns, organs that balloon for the short spring mating rush and then shrink back once the season ends. By packing more muscle and reproductive tissue into a still-tiny frame, the shrew does so before its brief 1.5-year lifespan runs out.
- Trowbridge's shrews are most common in autumn, with surveys showing they are roughly twice as abundant in the fall as in the spring. Their diet also leans toward plant matter more than any other Sorex species, snacking on Douglas-fir and pine seeds. they stay fed year-round without hibernating.
- From sea level up to 1,820 m (5,970 ft), Trowbridge's shrews cling to forest floors littered with leaves, twigs and downed logs. They can survive after logging as long as enough ground cover remains, hopping through dry, moist or swampy woods and even chaparral in southern California. On Destruction Island off Washington, they make homes in deep rank grass beside salmonberry patches, showing a knack for exploiting tiny pockets of shelter. Their ability to occupy such a range of habitats across the Pacific coast.
- Breeding seasons shift north to south: Washington shrews mate from March to May, while California populations stretch from February to June. Warmer climates also speed up sexual maturity, with males reaching readiness two weeks before females. In the north, fewer embryos are found and the season shortens.
- Fossils of Trowbridge's shrew have been pulled from the Carpinteria Tar Pits, dating back to the Wisconsonian (late Ranchlabrean) epoch at the extreme southern edge of its modern range. Scientists think the species originated earlier, but the West Coast lacks older fossil sites to prove it.
Sources
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At a glance
RangeNorth America
HabitatPacific coastal forests
DietInsects and seeds
About the Trowbridge's Shrew
In the damp, emerald understory of the Pacific Northwest, a tiny, frenetic silhouette darts through the shadows, as Trowbridge's Shrew embarks on its ceaseless quest for sustenance, its diminutive body a blur of motion as it navigates the labyrinthine network of leaf litter and twigs. With each twitch of its whiskered snout, the shrew probes the hidden recesses of its forest realm, uncovering a secret world of insect larvae and forgotten seeds. As it moves, the shrew's very existence seems a testament to the boundless vitality of this ecosystem, a reminder that even the smallest of creatures can play a profound role in the grand symphony of life.
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