A Type D personality is distressed, Type D's have a negative outlook towards life and are pessimistic. A small event that is not even noticed by type B can ruin type D's day. Type D personalities are more subject to depression than other personality types.
For most of human history, horses were seen as prey to be hunted for sustenance. During the late Pleistocene, around 55,000 years ago, Neanderthals scavenged off of horse carcasses and made occasional kills of their own.
Presently, the oldest undisputed evidence of horse domestication date back to 2,000 B.C., when horses were buried with parts of harnesses and chariots. A report published March 2009 suggested the Botai culture of Kazakhstan had domesticated horses as beasts of burden and to use their milk as a food source around 3500 B.C.