Those horse populations do well enough that the BLM regularly kills some off to limit the numbers. Ostensibly it's to protect the environment, but given the number of legal and illegal cattle that's allowed to graze on those same public lands I think the culling is mostly at the behest of ranchers.
https://stateline.org/2022/07/20/westerners-struggle-to-mana...
and while one can argue about the "true" motivations of the people arguing for culling/control, it's absolute true that conservation organizations think that feral horses are bad for the environment:
https://wildlife.org/wp-content/uploads/2017/05/FactSheet-Ho...
All equids evolved in North America. For tens of millions of years they were here, and only have been gone for ~10,000 years until being reintroduced by the spanish. [1]
[1] See the fantastic book "Twilight of the Mammoths"
The same that they eat in Chornobyl. Everything that is green except traffic lights.
This animal are the equivalent to "Eurasian zebras" and was designed to roam around in arid places. They are really hard and able to fend for themselves, even under high predatory pressure and radioactivity levels.