Opening this thread since
the original was too old.
IOTL, the Aborigines never formed a horse culture, despite many of their number becoming accomplished stockmen and horse riders after their conquest by the White Australians.
It seems to me that they never formed a horse culture because they never really got a chance. Once contact started, many of the Aborigines were blitzed over a matter of decades, whereas the Great Plains saw a good century+ of time between the Pueblo Revolt and a concerted colonization effort from a power that was not already overstretched (the French never had the numbers of the Americans, and the Spanish and later Mexicans always had issues projecting power northwards onto the plains).
Could an earlier European contact leading to a failed or incomplete colonization allow the creation of a horse culture? I'm thinking that the Dutch or Portuguese (more so the Dutch) could have made a go at a colonizing a portion of Australia in the 17th century, and then abandoned the colony either due to an Aboriginal 'Pueblo Revolt' or due to external factors, and leave behind livestock as well as Aboriginal and Metis servants/slaves trained in riding and ranching.
Over the 18th century the European powers ignore Australia as IOTL. This gives the Aborigine horse culture enough time to develop. The tribes closest to the colony, and therefore the more culturally disrupted, rebound fast as European diseases would have winnowed the old and left a demographically young society waiting for a population boom and a major change-they may even adapt pastoralism, as the escapees from the colony bring herds of animals in as they return to the tribes. Further out, the culture is more conservative and keeps hunting and gathering, but adapts the horse to supplement its hunting.
This culture will only have time to spread out over one region, IMO. Mountains and deserts will prevent the horse culture from spreading from coast to coast, and environmental and cultural factors will prevent all peoples from becoming 'horse peoples'-horses would have been pretty ridiculous in the Rocky Mountains or the Amazon, after all.
While they probably will be eventually colonized in the 19th century, the horse Aborigines may be able to put up a tremendous military resistance, resulting in much higher numbers going into the modern era. By driving away a 2nd wave of colonialism from one European power, they may open up a multi-state colonization of Australia through a 3rd wave from a different power.
Thoughts?