Case 1: In bottlenose dolphins, all individuals from a single ancestor use tools, while their companions (as in "member of the same group, but of different ancestor") do not use the tool.

Case 2: in chimps, tool use and learning most effective between age 3-5. A 16 year long longitudinal study.

Case 3: Archeologists find remnants of continued tool use on the same site for 4300 years.