Figure 1

Gallbladder bile color varies by season and hibernation. A) Photograph of bile collected from golden-mantled ground squirrels (Spermophilus lateralis) as a function of state. Bile was collected from squirrels collected monthly (2–3 squirrels per month) from May (left) until September (right; summer active, SA), squirrels during winter that were torpid (T) when body temperature was ~5°C, squirrels during the euthermic period between bouts of torpor (interbout-aroused; IBA), and squirrels that were sampled in winter but had failed to hibernate (abnormal, AB). As an indication of approximate volumes, microcentrifuge tubes contain all of the collected bile for each animal except one AB animal (full tube on lower right; ~2.5 ml of bile was collected from that animal). B) Spectral characteristics of bile as a function of state. Each line represents one animal. Data are depicted for 3 animals of each state and only every 50^th symbol is plotted for clarity.