FWS Focus

Overview

Characteristics
Overview

The Buena Vista Lake ornate shrew is a small mouse-sized mammal found only in the Tulare Basin of the San Joaquin Valley, California. It is one of nine subspecies of ornate shrew and is a member of the red-toothed shrew subfamily, which gets its name from the reddish, iron-based pigment that is thought to strengthen their tooth enamel and gives their teeth a red color. The Buena Vista Lake ornate shrew requires dense groundcover, to protect it from predators, and moist soil that supports diverse prey populations of insects, earthworms and other small invertebrates. 

The shrew’s historical range is thought to be within the moist habitat surrounding the wetlands of the Kern, Buena Vista, Goose and Tulare lakes on the San Joaquin Valley floor, below elevations of 350 feet. Much of the shrew’s original wetland habitat has been drained and converted to agricultural land, or is no longer suitable habitat due to changes in vegetation, and the spread of non-native plant species.

The Buena Vista Lake ornate shrew was listed as endangered in March 2002.

The species continues to be impacted by:

  • Habitat loss due to agricultural and urban development
  • Insufficient water supply due to drought and climate change climate change
    Climate change includes both global warming driven by human-induced emissions of greenhouse gases and the resulting large-scale shifts in weather patterns. Though there have been previous periods of climatic change, since the mid-20th century humans have had an unprecedented impact on Earth's climate system and caused change on a global scale.

    Learn more about climate change
  • Selenium and pesticide contamination

Scientific Name

Sorex ornatus relictus
Common Name
Buena Vista Lake ornate shrew
Buena Vista Lake shrew
FWS Category
Mammals
Kingdom

Location in Taxonomic Tree

Identification Numbers

TSN:

Characteristics

Characteristic category

Physical Characteristics

Characteristics
Color & Pattern

The Buena Vista Lake ornate shrew is grayish-black with a pale underbelly.

Size & Shape

The Buena Vista Lake ornate shrew is about the size of a mouse, but with smaller eyes, a longer, more pointed snout and five toes on their front feet, rather than the four that mice have. Like other shrews, this subspecies does not have the continuously growing front teeth that mice and other rodents use for gnawing.

Characteristic category

Life Cycle

Characteristics
Life Span

Ornate shrews live 12 to 16 months.

Reproduction

Ornate shrews are solitary and typically breed from early spring through May. Females establish territories that they tend to stay in their whole life, while males may travel between territories. Gestation lasts approximately 21 days, and females give birth to four to six young. Females nurse the young for less than a month. After they are weaned, the young leave to find their own territories.

Characteristic category

Similar Species

Characteristics
Similar Species
Characteristic category

Habitat

Characteristics
Habitat

Buena Vista Lake ornate shrews can be found near water sources in protective groundcover like deep leaf litter, cattails and fallen logs. The moist soil and dense cover hide the shrews from predators and attract insects, worms and other invertebrates that shrews eat. This subspecies can also sometimes be found in drier grassland and desert scrub within a few hundred feet of water sources, or where water is close to the surface and their prey can be found.

Grassland

Land on which the natural dominant plant forms are grasses and forbs.

Lake

A considerable inland body of standing water.

Rural

Environments influenced by humans in a less substantial way than cities. This can include agriculture, silvaculture, aquaculture, etc.

Wetland

Areas such as marshes or swamps that are covered often intermittently with shallow water or have soil saturated with moisture.

Springs or Seeps

Areas where ground water meets the surface.

Characteristic category

Food

Characteristics
Food

The Buena Vista Lake ornate shrew must eat every few hours, so it is active during day and night. The specific feeding and foraging habits of the Buena Vista Lake ornate shrew are not well known, but closely related species eat insects, sow bugs, centipedes, spiders, earthworms, slugs, springtails, small frogs and salamanders, as well as some plants and fungi.

Geography

Characteristics
Range

The shrew’s historical range is thought to be within the moist habitat surrounding the wetlands of the Kern, Buena Vista, Goose and Tulare lakes on the San Joaquin Valley floor, below elevations of 350 feet. Much of the shrew’s original wetland habitat has been drained and converted to agricultural land, or is no longer suitable habitat due to changes in vegetation, and the spread of non-native plant species.

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