Fun Science Facts from our Conservation Biologist Julie Grialou

Most of us have heard of the term “cold-bloodied” in reference to snakes. Snakes don’t really have cold blood (at least not all the time), but they are ectotherms and require heat from outside sources (e.g., the sun) to warm their bodies. This is in stark contrast to endotherms, like us humans and other mammals, who warm our bodies through metabolic processes.

So, what do snakes in the Methow do when temperatures drop and snow covers the ground? They hibernate. Snake hibernation sites are called hibernacula, aka snake dens. John Rohrer, USFS Biologist, and Dan Beck CWU Professor, conduct research on snake dens sites in the Methow. These researchers have found that den sites are almost always on south-facing slopes, which receive more solar radiation, and in areas that are sheltered from, wind, rain, and dripping snowmelt. The den sites must be deep enough to extend below the frost line and must be adequately ventilated. Interestingly, an individual den site is usually occupied by several snake species, and several hundred snakes can share one site. Photo by Mary Kiesau.

First published in November 2018