Final answer:
The discovery of a significant number of stone tools at the site of Pavo Real indicates that toolmaking was a primary activity performed there, reflecting practices of the Oldowan tool industry and social cooperation.
Step-by-step explanation:
One of the reasons archaeologists know toolmaking was a main task performed at Pavo Real is due to the discovery of a significant number of stone tools. This finding is suggestive of the site being a hub for the production of tools that were essential for various activities, such as hunting and processing meat. In granular detail, at sites like Atapuerca's Gran Dolina and Pavo Real, archaeologists found tools indicative of the Oldowan tool industry, which includes basic cutting flakes and core tools. Additionally, the presence of Oldowan style tools, constructed from local materials and designed from a technique that predates more sophisticated methods like the Acheulean bifaces, provides insight into the cognitive abilities of the toolmakers of that era. The absence of retouched tools at Gran Dolina coupled with evidence of social cooperation, such as food sharing and division of labor, also helps to paint a picture of the communal living and subsistence practices of ancient humans.