Darkness Induced Drinking

The Department of Experimental Pharmacology at the Southwest Foundation for Research and Education in San Antonio, Texas, subjected laboratory rats to various types of stress in an attempt to induce them to drink alcohol.

"The rats clearly preferred plain water except on weekends when they went on real alcoholic binges. This was perplexing at first but it was noted that the automatic time switch on the lights was out of order and the rats were being left in continuous darkness over weekends.