Asian Lesser White-toothed Shrew

Crocidura shantungensis is a small insectivorous shrew native to parts of East Asia, particularly the Korean Peninsula and Shandong region of China. It belongs to the white-toothed shrew group, characterized by unpigmented teeth unlike red-toothed shrews. This species is notable for its adaptability to a range of habitats including agricultural land and forest edges, making it a common small mammal in its range.

East Asia, including Korea (North and South), parts of China (Shandong Peninsula and surrounding areas), and Jeju Island; also recorded in Japan (Tsushima Island)

Distributed across the Korean Peninsula (both North and South Korea), the Shandong Peninsula of China, and offshore islands such as Jeju Island (South Korea) and possibly Tsushima Island (Japan)

Altitude and depth

Typically found from sea level up to mid-elevation areas, generally below 1500m

Seasonal movements

No long-distance migration; may show slight seasonal shifts in activity and foraging intensity related to temperature and food availability, particularly reduced activity in colder winter months

Found in a variety of habitats including grasslands, agricultural fields, forest edges, shrublands, and areas near human settlements. It shows tolerance for disturbed and semi-natural landscapes.

Adaptations to its environment

Possesses a high metabolic rate typical of shrews, requiring frequent feeding; small body size and efficient thermoregulation allow survival in temperate climates; keen sense of smell and touch (via vibrissae) compensate for poor eyesight in foraging for hidden invertebrates.

Listed as Least Concern (LC) by IUCN due to its relatively wide distribution, presumed large population, and tolerance of a variety of habitats including human-modified landscapes

Estimated population

No precise global population estimate available; considered common and stable within its range based on regional survey data

Habitat loss from urbanization and agricultural intensification, pesticide use reducing invertebrate prey base, and potential competition or hybridization pressures from related Crocidura species

Diseases and parasites

Known to host various ectoparasites such as fleas and mites, and may carry certain zoonotic pathogens common to shrews, though specific studies on this species are limited

No species-specific conservation programs are known; benefits indirectly from general habitat protection measures and protected areas within its range in Korea and China

Recommended actions

Continued monitoring of population trends, taxonomic clarification of subspecies and related populations, and protection of natural habitat mosaics including field margins and forest edges

Small shrew with a pointed snout, dense grayish-brown to reddish-brown dorsal fur, and paler grayish underparts; possesses tiny eyes and small external ears partially hidden in fur

Size

Body length approximately 55-75mm, with tail length of about 25-40mm

Weight

Typically weighs between 3 to 8 grams

Distinctive features

Distinguished from red-toothed shrews (genus Sorex) by white, unpigmented teeth; differentiated from closely related Crocidura species primarily through subtle skull and dental measurements and genetic analysis

Differences between males and females

Minimal sexual dimorphism; males and females are similar in size and coloration

Generally solitary and territorial outside of breeding season; individuals maintain separate foraging ranges with limited direct social interaction

When it is active

Primarily nocturnal and crepuscular, though may show some activity during daylight hours, especially when foraging demands are high due to fast metabolism

Diet

Insectivorous diet consisting mainly of invertebrates such as insects, spiders, earthworms, and other small invertebrates found in leaf litter and soil

How it feeds and hunts

Forages by actively searching through leaf litter, soil, and vegetation using its sensitive snout and whiskers to detect prey via touch and smell rather than sight

Communication

Communicates primarily through high-frequency vocalizations (some ultrasonic), scent marking via specialized skin glands, and tactile interactions using whiskers

Interactions with other species

Preyed upon by owls, small carnivorous mammals, and snakes; competes with other small insectivores for food resources; plays a role in controlling invertebrate populations

Role in its ecosystem

Functions as a mesopredator in the food web, helping regulate populations of soil and litter-dwelling invertebrates, and serves as prey for various small predators

Breeding season typically spans spring through autumn; gestation lasts approximately 25-30 days; litters usually contain 3-7 young

Raising the young

Females provide all parental care, nursing and protecting young in a nest until weaning, which occurs at around 3-4 weeks of age

Maturity and lifespan

Sexual maturity reached at around 2-3 months; lifespan in the wild is typically short, around 12-18 months, due to high predation and metabolic demands

Classification

Class Mammalia > Order Eulipotyphla > Family Soricidae > Genus Crocidura > Species Crocidura shantungensis

Subspecies

Taxonomic status debated; some authorities consider populations on Jeju Island and Tsushima as distinct subspecies or closely related forms, but no widely accepted formal subspecies list exists

Scientific synonyms

Previously included within Crocidura suaveolens complex; sometimes referenced as Crocidura suaveolens shantungensis in older literature

Recent studies

Molecular phylogenetic studies have helped clarify the taxonomic status of Crocidura shantungensis relative to Crocidura suaveolens and other regional shrews, resolving previous confusion in species boundaries

Genome and DNA

Genetic studies have been used to help distinguish this species from closely related Crocidura species within the suaveolens complex, though detailed genome sequencing data remains limited

Compared with similar species

Closely resembles Crocidura suaveolens (lesser white-toothed shrew) from which it was formerly considered a subspecies; distinguished mainly through genetic and subtle morphological differences rather than obvious external characteristics

Despite its tiny size, this shrew must eat nearly its own body weight in food daily due to an extremely high metabolic rate; it is one of the smallest mammals in its region and was only recently distinguished as a separate species from other white-toothed shrews through genetic research.

Where and how to see it

Best observed at dusk or dawn in grassy field margins, agricultural areas, or forest edges within its range in Korea; live trapping surveys are typically required for reliable detection due to its secretive and nocturnal habits

Risks to humans

No notable risk to humans; however, like other small mammals, it could theoretically carry parasites of minor zoonotic concern