I've seen the below graphic posted a number of times. It shows the total weight of horses approaching the same as all wild mammals combined. That part is hard to square up for me, is it really that bad?
Just did a quick calc based on googled US deer, elk, and horse population #'s. Rough numbers came out to horses having over twice the weight as deer and elk combined and I'm not even sure the horse #'s included the feral horses. Craziness. Sad that we'd allocate double the food resources to horses as wild ungulates.