[via Cooperation Commons and ] Augustin Fuentes at the University of Notre Dame hypothesizes that went extinct because early Homo(human ancestor) species were more adept at cooperating:
...Paranthropus suffered from increased predation because Homo, and other early humans even more closely related to modern humans, learned to use cooperation to avoid being eaten. He says all would have feared the same predators, such as big cats. To test the hypothesis, Fuentes's team designed a computer program based on classic ecology models to simulate how teamwork could have tipped the scales in favour of Homo. They found that just a moderate amount of teamwork gave Homo a dramatic advantage over its close competitors, causing the extinction of Paranthropus. The computer simulations add to real world evidence of co-operation in early humans. For example, the common use of stone tools by early humans suggests they shared information on the location of suitable stone. These sites are sometimes 30 kilometres away from where the tools are found and would not have been easy for individuals to find on their own. "This implies some sort of information transfer that's not language yet, but is much more extensive than that available to other organisms," Fuentes says.
Indeed, it seems that this primitive form of cooperation is now a central part of human existence world wide. Simple, narrow objective Human cooperation of the type Fuentes describes has been so successful, that it is now driving a huge portion of other species to extinction. It is cooperation based around physiological satisfaction. Cooperating to meet the very basic survival needs of existence.