A tiny gray form about two inches long darts frantically along a rotting log, leaps off the end, and scurries beneath a thick carpet of moss. It seizes its victim–an earthworm–and devours it almost instantly.
This energetic little beast is a shrew. It is mouse-like, but smaller, and also has a long, pointed, very unmouse-like nose. Shrews eat insects and other invertebrates. They must feed almost constantly to support their high metabolism . Shrews eat as much as three times their own weight each day. Their energy use in proportion to their size surpasses that of any other mammal.
Shrews have sharp, pincher-like teeth that are perfect for holding struggling insects and biting though their tough shells. Shrew saliva is laced with poison that slows down an insect’s heart rate and breathing.
Shrews often use mouse and mole tunnels, but sometimes dig tunnels of their own. Two shrews may even work together, one digging while the other packs the tunnel walls. Like bats, they make high-pitched noises that humans can’t hear. They use these sounds to locate objects in their tunnels.
Some shrews store live prey inside their tunnels and move it according to temperature, apparently to keep it immobile and fresh.
Shrews: Tiny but Toxic
- It may be small, but the shrew is mighty and full of energy.
- Shrews hunt constantly and burn energy so quickly that if they miss one meal, they might die.
- When stressed, a shrew’s tiny heart can beat up to 1,300 times per minute.
- Due to poor eyesight, a shrew sometimes just bumps right into its next meal.
- It can use high-pitched chirps, like a bat, to locate its prey.
- A shrew paralyzes prey with its fang-like teeth and poisonous saliva. It packs enough venom to kill 200 mice.
Information courtesy of the MDC’s Xplor Magazine.