Canary Shrew

The Canary Shrew is a small insectivorous mammal endemic to the eastern Canary Islands, primarily Fuerteventura and Lanzarote. It is one of the few native terrestrial mammals of this volcanic archipelago, having likely arrived via natural rafting or early human transport. Its restricted range and specialized habitat make it a species of significant conservation concern. It plays an important ecological role as an insect predator in arid island ecosystems.

Canary Islands, Spain (specifically Fuerteventura, Lanzarote, and adjacent islets)

Endemic to the eastern Canary Islands (Spain), found on Fuerteventura, Lanzarote, and several smaller surrounding islets such as Lobos and Alegranza. This represents an extremely restricted global range typical of island endemics.

Altitude and depth

0-800m, generally found at lower to mid elevations where suitable rocky and vegetated microhabitats persist

Seasonal movements

No true hibernation; may show reduced activity during extreme heat or drought periods, with breeding activity likely peaking during cooler, wetter months when insect prey is more abundant

Inhabits arid and semi-arid habitats including rocky areas, ravines (barrancos), agricultural margins, and areas with sparse vegetation cover. Often found near stone walls, rubble, and areas providing shelter and moisture retention in the otherwise dry volcanic landscape.

Adaptations to its environment

Exhibits physiological adaptations for water conservation typical of shrews in arid environments, including efficient kidney function and behavioral avoidance of peak heat through nocturnal/crepuscular activity. Its small size and high metabolism require constant foraging, so it relies on microhabitats with higher humidity and prey density.

Classified as Endangered (EN) by IUCN due to its extremely restricted range confined to a few small islands, ongoing habitat degradation, and vulnerability to introduced predators. Population is fragmented and sensitive to any localized environmental changes.

Estimated population

Population size is not precisely known but is considered small and fragmented; overall trend is believed to be declining due to ongoing habitat pressures

Habitat loss from urbanization and tourism development, predation by introduced species such as cats and rats, agricultural intensification, and potential competition with introduced shrew species. Climate change and increasing aridity also pose long-term risks.

Diseases and parasites

Specific data limited, but likely susceptible to common ectoparasites such as fleas and mites, and endoparasites typical of small insectivorous mammals

Protected under Spanish and EU wildlife legislation; some populations occur within protected areas such as natural parks on Fuerteventura and Lanzarote. Limited species-specific conservation programs exist, though habitat protection measures indirectly benefit the species.

Recommended actions

Increased habitat protection and restoration in key areas, control of invasive predators, population monitoring surveys, and research into distribution and genetic diversity across the islands to inform targeted conservation strategies.

Small shrew with grayish-brown dorsal fur and paler grayish-white underparts, a pointed snout, small eyes, and reduced external ears typical of the Soricidae family. Fur is short and dense.

Size

Head-body length approximately 5-7 cm, with a tail of about 3-4 cm

Weight

Typically weighs between 3-7 grams, among the smallest mammals in its range

Distinctive features

Distinguished from mainland Crocidura species by subtle differences in skull morphology, tooth pigmentation, and genetic markers; overall very similar in appearance to Crocidura russula but geographically and genetically distinct.

Differences between males and females

Minimal sexual dimorphism; males and females are similar in size and coloration with only slight differences in body mass

Generally solitary and territorial outside of breeding periods, as is typical for most shrew species, with individuals maintaining separate home ranges

When it is active

Primarily nocturnal and crepuscular, though may show some activity during daylight hours especially in cooler, cloudy conditions to avoid extreme heat

Diet

Insectivorous diet consisting mainly of arthropods including insects, spiders, and other small invertebrates found in leaf litter, soil, and rocky crevices

How it feeds and hunts

Forages by actively searching through vegetation, rocky crevices, and soil using its highly sensitive whiskers and snout to detect prey through touch and smell, given poor eyesight

Communication

Communicates through high-frequency vocalizations (some possibly ultrasonic), scent marking via glandular secretions, and tactile whisker-based sensing for navigation and social interaction

Interactions with other species

Preyed upon by introduced predators such as feral cats and possibly owls and other raptors; may compete with introduced rodent species for resources in shared habitats

Role in its ecosystem

Functions as an insectivorous predator helping regulate arthropod populations within its island ecosystem, contributing to the broader food web as prey for birds and mammalian predators

Breeding likely occurs during favorable seasons with adequate food availability; gestation period is short (around 28-30 days typical of Crocidura genus) with litter sizes of 2-6 young

Raising the young

Females provide sole parental care, nursing and protecting the altricial young in a nest until weaning, which occurs within a few weeks after birth

Maturity and lifespan

Sexual maturity likely reached within a few months of birth; lifespan in the wild is short, typically 1-2 years, consistent with other small shrew species

Classification

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

Scientific synonyms

Sometimes previously included within Crocidura russula as a subspecies; taxonomic status has fluctuated between full species and subspecies designation

Recent studies

Recent phylogenetic research has focused on clarifying the evolutionary relationships and colonization history of Crocidura canariensis relative to North African and European Crocidura species

Genome and DNA

Genetic studies have helped clarify its taxonomic distinction from mainland Crocidura russula populations, supporting its status as a separate endemic species

Compared with similar species

Closely related to Crocidura russula (greater white-toothed shrew) from mainland Europe and North Africa, but distinguished by genetic divergence and isolation on the Canary Islands, along with subtle morphological differences

This tiny shrew is one of the very few native land mammals of the Canary Islands, most of which are otherwise dominated by introduced species. Despite its diminutive size, it must eat frequently due to an extremely high metabolic rate typical of shrews.

Where and how to see it

Best observed at dusk or dawn in rocky ravines and rubble-strewn areas on Fuerteventura and Lanzarote; patience and quiet observation near stone walls or agricultural edges increase chances of spotting this elusive, fast-moving mammal

Risks to humans

No notable risk