Family: Soricidae (Shrews)
Family: Talpidae (Moles)
Shrews, the smallest mammals, are also important because they represent the most primitive mammals. Their characteristics most closely resemble primitive mammals that fossil evidence indicates evolved during the era of dinosaurs. As the name implies, they feed primarily on insects and other small invertebrates. This order includes two families, Soricidae, the shrews and Talpidae, the moles. In Idaho, we have relatively few species.
Shrews include the smallest known mammals. Because of their small size they have an extremely large surface area relative to their body volume. Hence, they lose body heat very rapidly, which requires an extremely high metabolic rate to accommodate the loss of body heat energy. They are inactive for only short periods of time, typically feeding and eating about every 3 hours with rest periods between feeding activity. Because of this high metabolic rate and voracious appetite, some shrews will eat up to twice their body rate per day. Shrews typically forage along the surface of the ground in the duff layer of vegetation for their food. Some shrews actually use a echolocation to navigate about their environment. Shrews have a pointed snout, very small eyes, and small ears which typically are hidden in their fur.
The only mole in Idaho is the Coast mole and it is only found in the extreme western edge of the state. Moles are larger than shrews but have shorter tails. They are primarily fossorial, or burrowing mammals. Like shrews, their fur is short and almost like velvet which allows them to squeeze through the soil in their burrows in either direction with little resistance. Moles are very well adapted to burrowing; their front legs have enlarged feet and claws for digging and are angled outward to accommodate a "breast stroke" type digging. Their pelvis is very narrow to accommodate changing directions in their small burrows. Their eyesight is poor, but they have excellent smell and touch with their snout which enables them to detect and catch their prey such as earthworms.
Information by Donald
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