Recent sub-zero wind chills have been tough on people, but wildlife faces even greater challenges during harsh winter weather. During a recent appearance on the Outdoors in North Iowa podcast, Butler County Naturalist Annette Wittrock said animals use a variety of strategies to survive, including migration, hibernation and insulating fur or feathers.
She notes that small mammals like mice and voles actually rely on snow for protection, living beneath the snowpack.
“Those animals actually live in what’s called the subnivean zone. Sub means below and nives meaning snow. Snow covering the ground insulates these small animals against the cold temperatures above and it shelters them from the cold winds as well. Plus it offers a small layer of added protection from predators. They have access to unfrozen seeds and other foods in this space as well. In fact, they only need about six inches of snow to have a sturdy roof over their heads. If you add two more inches to that, the subnivean zone will stay within two degrees of the freezing mark no matter what the temperature or weather is above the snow.”
However, with warmer temperatures expected in the coming days, melting snow could expose these animals to predators and reduce their winter shelter.
“As we’ve seen this year, the snow that fell early in the season eventually melted away. When this happens, they have to rely on good hiding spots and underground areas while foraging for food to stay safe from the predators. But those predators can even hear or smell them through the snow and that fox and coyotes can smell them even with the snow cover. So all those animals also have the ability to break through the snow with their feet to capture those animals.”
Wittrock says when snow melts, the tunnel systems become visible, offering a brief glimpse into how these animals survive winter before spring growth erases the tracks.
Full interview below
