European ground squirrel
... that while the European ground squirrel is hibernating, it may use up 90% of its fat reserves?
... that while the <b id="mwSQ"><a href="./European_ground_squirrel" id="mwSg" rel="mw:WikiLink" title="European ground squirrel">European ground squirrel</a></b> <i id="mwSw">(pictured)</i> is <a href="./Hibernation" id="mwTA" rel="mw:WikiLink" title="Hibernation">hibernating</a>, it may use up 90% of its fat reserves?