Big game hunting is another great achievement of Homo erectus.

There was a time when hominids were vegetarian. It is interesting that many of us are turning vegetarian again. Does it tell us anything?
An interesting way of looking at meat eating:

Meat-eating provided concentrated protein. It released meat-eaters form the incessant nibbling of so many vegetarian creatures, and so permitted economies of effort.

Meat eating must have started with scavenging and then moved on to hunting bigger animals. By around three hundred thousand years ago hunting must have been the primary source of food. Big game hunting must have involved careful planning, extreme skill (something never needed before) and involvement of a large group. Since little or no weapons were available, such hunting was possible only in areas which provided natural traps like a precipice or a bog where heavy creature would not be able to move properly.
Search for big game and favorable terrain led to exploration and new settlements especially to areas favoured by the mammoth or wooly rhinoceros.