Origin of the domestic dog them to more successfully adapt to the human habitat. Even today, the wolves on Ellesmere Island do not fear humans, which is thought to be due to them seeing humans so little, and they will approach humans cautiously, curiously and closely. Some studies have found greater diversity in the genetic markers of dogs from East and Central Asia compared to Europe and have concluded that dogs originated from these regions, despite no archaeological evidence to support the conclusions. One reason for these discrepancies is the sustained admixture between different dog and wolf populations across the Old and New Worlds over
Dog type were described as species by Johann Friedrich Gmelin in 1788, and by Robert Kerr in his English translation of "Systema naturae" ("The Animal Kingdom") in 1792. Today the species Linnaeus named are identifiable as dog types, not species or subspecies. Some, such as "Canis aegyptius", a hairless dog type of Peru, have been documented and registered as breeds (Peruvian Hairless Dog). There are only two categories (subspecies) of domestic dog, "Canis lupus familiaris" and "C. l. dingo", recognized by the International Code of Zoological Nomenclature (ICZN Code). Beginning with the advent of dog shows in the mid-19th century in England,