White-toothed Shrew

How big are white-toothed shrews compared to other small mammals?

White-toothed shrews (genus Crocidura) exhibit a significant range in size, reflecting the diversity of the 164 species within the genus. Compared to other small mammals, they occupy the lower end of the size spectrum:¹

• Smallest Species: The pygmy white-toothed shrew (Suncus etruscus) is among the smallest mammals known, weighing between 1.2 and 2.7 grams with a body length of 4 to 5 cm. Similarly, the Sulawesi tiny shrew (C. levicula) weighs about 4 grams with a 6 cm body.²¹
• Largest Species: Olivier’s shrew (C. olivieri) is one of the larger members, weighing 37 to 78 grams with a body length of 11 to 15 cm. For context, this is still smaller than the armoured shrew (Scutisorex somereni), which can weigh up to 113 grams, or the Sulawesi spiny rat, a rodent that can reach 310 grams.¹²³
• General Comparison: Most white-toothed shrews are mouse-sized. They are generally comparable to the common Eurasian shrew, which averages 14 grams and 6 to 8 cm in body length.¹²

What are some unique adaptations of white-toothed shrews?

White-toothed shrews (genus Crocidura) possess several specialized adaptations that allow them to thrive in diverse environments ranging from tropical forests to grasslands. Key features include:⁴

• Feeding Mechanics: Unlike many other small mammals that use their paws to handle food, white-toothed shrews use their highly flexible, mobile snout (proboscis) to manipulate prey. They use their hooked upper incisors like forceps to capture insects, arthropods, and earthworms.¹⁴
• Sensory Specialization: While their eyes are small, they possess an enhanced sense of smell, supported by prominent olfactory lobes in the brain. Their snouts are also covered with long, sensitive whiskers that aid in navigation and prey detection.¹⁴
• Physical Traits: As their name suggests, they have white teeth, which are not replaced throughout their lives. Their bodies are cylindrical with short, slender limbs, and some species feature long, bristly hairs (vibrissae) scattered across their finely furred tails.¹⁴
• Chemical Defense: Like other members of the family Soricidae, they possess scent glands on their flanks and other body parts that produce a foul odor, likely serving as a deterrent to predators.¹

Where are white-toothed shrews typically found in terms of geographical distribution?

White-toothed shrews (genus Crocidura) are widely distributed across Africa, Europe, and Asia.¹²

• Africa: This continent holds the greatest diversity, with 106 species distributed throughout the region, excluding some Saharan areas.¹
• Asia and Europe: Fifty-three species range from Asia Minor eastward to Southeast Asia, including various islands such as Taiwan, the Philippines, and Sulawesi. Their range extends across the Malay Peninsula and through the Sunda Islands to Aru Island.¹
• Habitats: They are highly adaptable, inhabiting temperate and tropical forests, riverine forests, marshes, savannas, grasslands, and semiarid regions. They generally avoid harsh deserts, tundra, and taiga environments.¹

Because they are found on multiple continents and diverse island chains, they are considered one of the most widespread groups of small mammals.¹

How do white-toothed shrews differ from other shrew genera?

White-toothed shrews (genus Crocidura) are distinguished from other shrew genera primarily by their dental characteristics and their high level of species diversity. While many other shrews are categorized as “red-toothed” (such as those in the genus Sorex), white-toothed shrews possess teeth that remain white throughout their lives and are not replaced.¹⁷⁸

Beyond their dental features, they differ from other groups in the following ways:

• Taxonomic Diversity: Crocidura is the most species-rich genus of mammals, containing over 164 species. They belong to the subfamily Crocidurinae, which includes nine other genera, such as Suncus and Sylvisorex, but they are distinct from the subfamilies Soricinae and Myosoricinae.¹⁵
• Physical Adaptations: Unlike burrowing shrews (such as Blarina or Feroculus), which have minute eyes and long digging claws, white-toothed shrews have small eyes but relatively large ears. While many shrews are strictly terrestrial, some Crocidura species are agile climbers that forage in trees and bushes, a trait they share with forest musk shrews (Sylvisorex).¹²
• Feeding Behavior: A unique behavioral adaptation of white-toothed shrews is their use of a highly mobile, flexible snout (proboscis) to manipulate prey, rather than relying on their paws.¹