| Abstract: | The night time behavior (1900-0700) of 12 stallions was observed using videorecording. All of the stallions masturbated sometime during the night for an average of 3.3 bouts lasting 3.0 + 0.4 min. Ten of the 12 stallions lay down during the night for bouts lasting 14.5 + 2.1 min. Both lying and masturbation occurred most frequently in the early morning hours. Forty percent of the bouts of lying were followed within 5 min by bouts of masturbation indicating that there may be association between REM sleep, which occurs only during recumbent rest in horses, and masturbation. These results suggest that nocturnal bouts of masturbation may be used to distinguish psychogenic from physical causes of impotence in horses. |
