Comment by t344344

So is mice, lizard and so on.

But there are huge differences:

* Primates can not sweat and self regulate body temperature through perspiration.

* Primates can not fast, most humans can go 40 days without eating, chimps would starve to death after couple of days.

* Primates can not run for several hours and outrun a horse!

Scaling up brain is not a problem, but keeping it supplied with energy is.