Trowbridge's shrew facts for kids
Quick facts for kids Trowbridge's shrew |
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| Conservation status | |
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Sorex
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| Species: |
trowbridgii
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| Trowbridge's shrew range | |
The Trowbridge's shrew (Sorex trowbridgii) is a small mammal that belongs to the shrew family, Soricidae. You can find these shrews in southern British Columbia in Canada. They also live in the United States, specifically in Washington, Oregon, and California.
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Discovering the Trowbridge's Shrew
Scientists first described the Trowbridge's shrew in 1857. It was named by Spencer Fullerton Baird. He found them while exploring for a railroad route from the Mississippi to the Pacific Ocean.
The scientific name Sorex trowbridgii has a special meaning. Sorex is a Latin word for "shrew-mouse." The name "trowbridgii" honors William Petit Trowbridge. The first shrews studied came from Astoria, Oregon.
What Does a Trowbridge's Shrew Look Like?
Trowbridge's shrews are medium-sized with a long tail. They usually weigh around 3.8 g (0.13 oz) when not breeding. Breeding shrews are a bit heavier, about 5 g (0.18 oz).
Their fur changes color during the year. In summer, their coat is darker and brownish. In winter, it becomes lighter gray. They have long whiskers and furry ears. These shrews also shed their fur twice a year. The winter coat is thick and gray, while the summer coat is lighter and dark brown.
Young shrews have hairy tails. As they get older, their tails become less hairy. The tail has two colors: darker on top and lighter on the bottom. There's a clear line between the colors. This helps tell them apart from other shrews. Their feet are light-colored, from whitish to light tan.
Their teeth have dark reddish-brown tips. A special feature is that their third upper tooth (called a unicuspid) is smaller than the fourth. This helps scientists identify them.
Where Trowbridge's Shrews Live
Trowbridge's shrews live along the western coast of North America. You can find them in the very southwest part of British Columbia, Canada. They also live in western Washington and Oregon.
In northern California, their home range splits. One part goes south along the coast to Santa Barbara County. The other part goes south through the Sierra Nevada Mountains to Kern County. They live from sea level up to about 1,820 m (5,970 ft) high.
These shrews prefer forests with lots of ground cover. This cover can be fallen leaves or branches. They can stay in an area even after logging if there's enough cover. They live in both dry and moist forests, and even in swampy areas. Some shrews on Destruction Island live in tall grass near salmonberry plants. They are less common near streams. In warmer, southern areas, they might live in chaparral, which is a type of shrubland.
Behavior and Life of the Shrew
Trowbridge's shrews play an important role in their environment. They are hunted by birds like the barred owl. The Pacific giant salamander also eats them. House cats might kill them but usually don't eat them. Shrews can also have parasites like ticks, mites, and worms.
Since these shrews are caught most often in their habitat, scientists believe they are very common.
Trowbridge's shrews live for about 1.5 years. They do not hibernate, meaning they stay active all year long. There are usually twice as many shrews in the fall as in the spring.
What Trowbridge's Shrews Eat
Insects are a main food source for these shrews. They also eat spiders, worms, and centipedes. Scientists have found centipedes, spiders, and slugs in their stomachs. They eat the most food during their breeding season.
Unlike some other shrews, Trowbridge's shrews eat more plants. In winter, they might eat seeds from trees like Douglas-fir and pine.
Reproduction and Life Cycle
As Trowbridge's shrews get ready to breed, they gain weight. Males' reproductive organs grow, and females' reproductive parts widen. After the breeding season, these parts shrink back down. Shrews in warmer areas might start breeding earlier. Males seem to become ready to breed about two weeks before females.
Female shrews can become pregnant again while they are still nursing their young from a previous litter. They usually have about 3 to 5 babies at a time. In northern areas, shrews tend to have fewer babies, and their breeding season is shorter. The breeding season runs from March to May in Washington. In California, it lasts longer, from February to June.
Shrews and People
Scientists have studied how logging affects Trowbridge's shrew populations. The results have been mixed. Some studies showed an increase in shrews, while others showed a decrease.
Protecting Trowbridge's Shrew
The IUCN (International Union for Conservation of Nature) lists Trowbridge's shrew as "Least Concern." This means they are not currently at risk of disappearing. This is because their population is stable, they don't have many major threats, and they live in a wide area. Also, there are many protected areas where they live.
Images for kids
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A Trowbridge's shrew.
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Map showing where Trowbridge's shrews live.
