Figure 4

Example near-real time data acquired from denning bears. A dramatic reduction in activity and heart rate variability was observed in pregnant females post parturition (such as 4011 shown here), whereas a constant level of activity and heart rate variability was maintained throughout the winter for the female denning with yearlings (4067). (Note: To calculate heart rate variability, the device measures each ventricular interval and calculates the median interval every 5 min. The heart rate variability value (in ms) for each day is then calculated as the variability seen in the 5-minute median values over the 24-hour period [19]).