A Review of Black Skin Research: Gloger Rule/Theory Dead or Alive?

Unlike various topics of human life that recurringly naggingly preoccupy scholars, black skin tends to be considered by prestigious biology and science publication outlets as a closed and disposed-of topic. The present paper is not one of experiment, but rather the paper is a long-due comprehensive review of black skin scholarship, using a dominant theory of this scholarship, and suggesting newer insights for future research. Known since Antiquity, black skin -- euphemistically called dark sin -- has become the topic of repeated public debate in recent decades. Part of the reason is that although race is believed to be scientifically nonexistent skin color is not. Meanwhile, among the theories explaining black skin, Gloger rule/theory stands out to be the most popular. While multitudes of reviews have examined Gloger theory, few have confronted the theory with the arguments of Gloger himself. This might be because Gloger writings remain untranslated and unknown to English readership. Although Gloger was an ornithologist by profession, his arguments had immense ramifications far beyond the study of birds. The present paper focused on the key arguments of Gloger to present a critical assessment of black skin materials. To this effect, a comprehensive, historical background of Gloger theory was used along with recent research to bring in sharper relief Gloger teachings about skin color. In light of Gloger critiques, it was determined that Gloger theory is no less than inadequate and so is the description of black skin as a product of natural selection. Taken-for-granted theories and resultant arguments of black skin were reversed and paths for future skin color work were proposed. Gloger arguments highlight variability among species and across latitudes.