Bone tools dating between 2.3 and 0.6 mya have been found in abundance in Swartkrans, Kromdraai, and Drimolen Caves, and are often associated with "P. robustus". Though "Homo" is also known from these caves, their remains are comparatively scarce to "Paranthropus", making "Homo"-attribution unlikely. The tools also cooccur with "Homo"-associated Oldawan and possibly Acheulian stone tool industries. The bone tools were typically sourced from the shaft of long bones from medium- to large-sized mammals, but tools made sourced from mandibles, ribs, and horn cores have also been found. Bone tools have also been found at Oldawan Gorge and directly associated with "P. boisei", the youngest dating to 1.34 mya, though a great proportion of other bone tools from here have ambiguous attribution. Stone tools from Kromdraai could possibly be attributed to "P. robustus", as no "Homo" have been found there yet.