Thermal conservation is critical to the success of small mammals, which have a large surface area to volume ratio. To reduce heat loss, squirrels den in tree cavities where available, and in winter months, especially during high winds (> 4 m/s) (Koprowski, 1994), squirrels spend more time in tree cavities and leaf nests than during summer. In a study by Stephen P. Havera, occupied squirrel nesting boxes, which provide insulation similar to tree cavities, were an average of 25.9° C warmer than the ambient temperature. The nest box’s lowest temperature was 8.3° C when the ambient temperature was -20.0° (Havera, 1979). Tree cavities with small opening also block wind, keeping squirrels warmer during storms.
Location: United States, South Dakota, McCook
Image Date: 2009JAN08
Image Species: Sciurus niger rufiventer
(EXIF infomation is accurate – stamped in UTC).
Web Page and Pictures By Hannah Leitheiser