Apologies, appeared I forgot to paste the link!
The article talks about how in hot weather, humans have a great advantage with our great ability to sweat. Combine this with slow twitch muscles and a social hunting group, and we can outlast our prey using 'persistence hunting.'
It uses the man vs. horse race as an example. Where practiced runners compete in a 22 mile race against your run of the mill horse, and sometimes win. Most likely because the heat just makes it hard for the horse, but a human can efficiently shed that heat.
Entertaining to read.