Development of behavior: the micturition pattern in the dog.

Abstract

22 dogs, 16 [male][male] and 6 [female][female], were experimentally treated as follows: with sex hormones, delayed on a treadmill apparatus, and rendered anosmic or castrated. Littermate controls were used in studying the effect of the urination posture under the exptl. conditions. Normal [male] puppies did not elevate the leg when urinating until 19 weeks old at the earliest or 43 weeks at the latest in the group studied. Normal [female][female] never elevated the leg when urinating. Castrated [male][male] did not elevate the leg unless treated with testosterone propionate. The castrated animals reverted to the puppy urination posture when testosterone was no longer injd. A puppy elevated the leg during urination when 8 weeks old after being treated with testosterone. It was found possible to disrupt leg-elevation behavior in normal adult [male] dogs by injn. of [female] sex hormones. The leg-elevation pattern in [male][male] followed a proximo-distal direction of development. Some [male][male] revealed a preference for raising the right or left leg. A hypothesis based upon varying amts. of hormones crossing different thresholds to activate appropriate neuromuscular patterns is suggested. The leg-elevation behavior in [male][male] is considered too unlearned and sufficiently complex to be called an instinct.