Fig. 1
Freezing behavior during exposure. Freezing time during the 10-min exposure session in control (n = 23) and fox-urine exposed (n = 62) groups. a Diagram of experimental schedule. b Fox-urine exposed animals showed a significantly longer freezing time (left, p < 0.0005, in percentage) and greater mean distance (right, p < 0.0007, in meters) from the cotton pad than controls. c The distributions of individual animals’ freezing time in the control group (left) and the exposed group (right) displayed as probability histograms. The freezing time distribution in exposed animals was fit to a Gaussian mixture model, which demonstrated a bimodal distribution. d Freezing time each min plotted as a function of time in low-freezing (n = 21), high-freezing (n = 21) and control animals during fox-urine exposure. The high-freezing animals displayed higher freezing phenotype during the first minute of exposure, with a significantly longer freezing time than both low-freezing and control animals from the 1st minute through the 10th minute (p < 0.005 for each minute of exposure). Bars indicate s.e.m. Source data of Fig. 1b–d are provided as a Source Data file
