section_path: Animals/Mammals
section_name: Mammals
paragraph_text: Mammals
  
  The beginnings of animal domestication involved a protracted coevolutionary process with multiple stages along different pathways. There are three proposed major pathways that most animal domesticates followed into domestication:
  
  Humans did not intend to domesticate animals from either the commensal or prey pathways or at least they did not envision a domesticated animal would result from it. In both of those cases, humans became entangled with these species as the relationship between them intensified, and humans' role in their survival and reproduction gradually led to formalized animal husbandry. Although the directed pathway for draft and riding animals proceeded from capture to taming, the other two pathways are not as goal-oriented, and archaeological records suggest that they took place over much longer time frames.
  
  Unlike other domestic species selected primarily for production-related traits, dogs were initially selected for their behaviors. The dog was domesticated long before other animals, becoming established across Eurasia before the end of the Late Pleistocene era, well before agriculture.
  
  The archaeological and genetic data suggest that long-term bidirectional gene flow between wild and domestic stocks – such as in donkeys, horses, New and Old World camelids, goats, sheep, and pigs – was common. Human selection for domestic traits likely counteracted the homogenizing effect of gene flow from wild boars into pigs, and created domestication islands in the genome. The same process may apply to other domesticated animals.
  
  The 2023 parasite-mediated domestication hypothesis suggests that endoparasites such as helminths and protozoa could have mediated the domestication of mammals. Domestication involves taming, which has an endocrine component; and parasites can modify endocrine activity and microRNAs. Genes for resistance to parasites might be linked to those for the domestication syndrome; it is predicted that domestic animals are less resistant to parasites than their wild relatives.