Cats come in all sizes, some have been domesticated while others are wild animals. The differances between wild and domestic cats could shed light on the evolutionary pathway that has led to cats as human companions. Typically untrainable, cats would not have been selected for in early agricultural communites like dogs and horses were. The inability to get a cat to follow commands makes them practically useless as helpers.
It is hypothesized that cats became integrated into human society as they exploited early civilaztions that often became overrun with prey species such as mice. Humans tolerated the presence of wild cats as they began to incorporate themselves into the human world. The process is described as one of natural selection in contrast to the artificial selection that has created the domesticated dog. Through time and evolutionary adapatations, the more docile and agreeable cats were then transplanted by humans across the globe.
Domestic cats, F. silvestris catus, are a subspecies of cats that evolved from wildcats that had chosen to live in and close to human settlements like in the Fertile Cresecent. Genotyping of domestic cats has shown that they are derived from five lineages and can be traced back to F. silvestris lybica. Fossils and ancient art places the domestication of cats at around 11,000-4,000 B.P . These data also suggest that there was a singular domestication event that began the process.
Mitochondiral DNA analysis of domesitcated cats suggests that divergence from the wild cats occured in sympatry. There is a marked phenotypic divergence in behavior of domestics and their less tame wild counterparts. Genes that made wild cats better suited to urban lifestyles were selected for geographically and concurrantly with humans. The great diversity in housecats can be attributed to geographic dispersal along the Fertile Crescent and the thousands of years of evolution towards an increase in domestic genes in cat populations that integrated themselves into human settlements. The human preference for tameness provided an avenue for the translocation of tame cats to new settlements as human expansion continued. The adorable cats that we now snuggle in our homes are the result of wild cat’s exploitative behaviors that evolved into tamenss with increasing human contact.
 Driscoll, C. A., et al. “From Wild Animals to Domestic Pets, an Evolutionary View of Domestication.” Proceedings of the National Academy of Sciences, vol. 106, no. Supplement_1, 2009, pp. 9971–9978., doi:10.1073/pnas.0901586106.