Why has animal husbandry become the main branch of the Mongolian economy?

The development of animal husbandry is facilitated by the natural and geographical conditions of Mongolia. It is unproductive to fish in it, there are few rivers, and it is difficult to grow crops because of the marginal soil and the harsh climate, the summer is short and sometimes cold.
There are all the conditions for animal husbandry in Mongolia: the harsh climate is not particularly and interferes with horses, sheep and rams. Huge steppe areas, enough forage, low population density. Animal husbandry provided the Mongols with food, milk, transport and clothing.