Figure 4.

Thermal preferences for stimulation of the paws of 8 male and 17 female hooded rats (upper panel) and 6 male and 6 female hairless rats (lower panel). Each plot was constructed by subtracting the first time of occupancy on the cold plate from the first duration on the hot plate and so forth, response by response, up to 15. The hooded females spent nearly equal time on the hot (45°C) and cold (10°C) plates, but the males strongly preferred the cold side (relative heat aversion), even though the hot plate temperature was set 2°C lower than for females. The hairless males spent approximately equal time on the hot and cold plates, but the females strongly preferred heat (relative cold aversion).