Fig. 6

Heart rate (HR) changes automatically recorded on 17-Dec-09 using a Generation 2 (GEN 2) device with conventional software during a visit to the den of a wild female bear hibernating with yearlings in Minnesota. Panels show HR trends: prior to the research team’s arrival at the den [slow HR with respiratory sinus arrhythmia (RSA)], after arrival (team arrived at 9:30 AM; respiration rate noticeably elevated), while the anesthetic was taking effect (increase in HR and attenuation of RSA), and of the fully anesthetized animal (no RSA; steady rate of 120 bpm; likely associated with autonomic suppression). The downward excursions in the plot correspond to the respiratory cycling