Using microscopes and image resolution software, they examined scratch marks on the bones. The scratches on the bones belie scientists' earlier belief that they were used for tuber-digging, the team reports in the 16 January Proceedings of the National Academy of Sciences . Bone tools created by other researchers show angular marks when used to dig for tubers. The Australopithecus tools, in contrast, had striations running parallel to the bone's axis. This pattern closely matches the marks found on experimental bone tools used exclusively for opening up termite mounds.
Termites apparently are well worth all the trouble.
While a rump steak yields only 322 kilocalories per 100 grams, termites are good for 560 kilocalories.