Shrews, belonging to the family Soricidae, are tiny, high-energy mammals that play crucial roles as insect predators in ecosystems worldwide.
- Shrews are members of the family Soricidae.
- They are small, with some species among the smallest mammals.
- Shrews have a very high metabolic rate, requiring almost constant feeding.
- They are primarily insectivorous, feeding on insects, worms, and other invertebrates.
- Shrews have sharp, sometimes venomous, teeth adapted for their diet.
- Their ecological role includes controlling insect populations.
*Soricidae*
Extremely high metabolic rate
Invertebrates
Predators of invertebrates
Physical Characteristics
Shrews have elongated, pointed snouts and tiny eyes, providing them with excellent senses of smell and touch to locate prey.
- Shrews are very small, often mouse-like in appearance.
- They have elongated, pointed snouts.
- Their eyes are small, with limited vision.
- Shrews rely heavily on smell and touch for hunting.
- Their fur is typically dense and velvety.
- Shrew teeth often have red pigmentation due to iron, enhancing durability.
Elongated and pointed
No, shrews have sharp, spike-like teeth
Highly developed smell and touch
Dense and velvety
Red pigmentation from iron
No, their vision is poor
Example Genera and Species
- Sorex: The most widespread genus of shrews
- Crocidura: Known as white-toothed shrews
- Neomys: Water shrews with semi-aquatic habits
- Blarina: Includes some of the only venomous mammals (blarina shrews)
| Genus | Notable Traits | Example Species |
|---|---|---|
| Sorex | Typical shrews, widespread | Sorex araneus (Common shrew) |
| Crocidura | White-toothed, very diverse | Crocidura russula (Greater white-toothed shrew) |
| Neomys | Water shrews, semi-aquatic | Neomys fodiens (Eurasian water shrew) |
| Blarina | Venomous saliva, robust body | Blarina brevicauda (Short-tailed shrew) |
*Sorex*
They are 'white-toothed' shrews
*Blarina*
Distribution and Habitat
Shrews have a nearly global distribution, absent only from Australia and most of the Southern Hemisphere.
- Found on every continent except Australia and Antarctica.
- Most diverse in the Northern Hemisphere.
- Inhabit forests, grasslands, wetlands, and even gardens.
- Some species are fossorial (burrowing), others are terrestrial or semi-aquatic.
- Prefer moist environments to prevent dehydration due to high metabolism.
Forests, grasslands, wetlands
Near water bodies
Some species are found in tropical regions
Behavior and Ecology
Shrews are voracious predators of insects and other invertebrates, some species possessing venomous saliva to immobilize prey.
- Mostly nocturnal or crepuscular.
- Have high reproductive rates due to short lifespans.
- Use sharp, spiny teeth to capture and consume prey.
- Some species use echolocation for navigation.
- Can be aggressive, even toward their own kind.
- Important in soil aeration and pest control.
- Some species store food for winter survival.
Yes, some species have venomous saliva
They have a high reproductive rate
Most shrews do not hibernate; some store food
Fossil Record and Evolution
Shrews have one of the longest mammalian fossil records, dating back over 60 million years to early eulipotyphlans.
- Fossils date to the Paleocene, >60 million years ago.
- Early shrew-like mammals were part of Eulipotyphla.
- Shrew fossils show remarkable stability in form (conservative evolution).
- Modern Soricidae diversified in the Cenozoic Era.
- Close relatives include moles and hedgehogs.
- Fossil teeth are often used for identification due to durability.
Over 60 million years
During the Cenozoic Era
Shrews (Soricidae) are remarkable for their tiny size, voracious appetites, and pivotal roles as invertebrate predators in diverse ecosystems worldwide.
- Shrews are insectivorous mammals with high metabolic rates and specialized teeth.
- They occur globally except in Australia and Antarctica, inhabiting moist environments.
- Their evolutionary history traces back over 60 million years to early eulipotyphlans.