Extracting Bone Marrow by Percussion Splitting — Prehistoric Calorie-Dense Food Processing

Bone marrow was one of the most calorie-dense and nutritious foods available to prehistoric humans — a single femur from a large ungulate like a deer yields 50 to 100 grams of marrow containing roughly 800 calories per 100 grams, predominantly monounsaturated and saturated fats along with protein, iron, and fat-soluble vitamins A and K. Archaeological evidence of intentional percussion-fractured long bones for marrow extraction dates back over 2 million years at sites like Olduvai Gorge in Tanzania and Swartkrans in South Africa, making it one of humanity's earliest food-processing activities. The technique exploits the structural geometry of long bones: the shaft (diaphysis) is a hollow cylinder of dense cortical bone surrounding a marrow cavity, while the rounded ends (epiphyses) are spongy trabecular bone with little accessible marrow. By striking the mid-shaft against a stone anvil with a hammerstone, the bone splits cleanly along its long axis, exposing the soft fatty marrow inside. Marrow can be eaten raw — it has a rich, buttery flavour and smooth texture — or added to hot-stone broth for calorie enrichment. This blueprint teaches the complete anvil-and-hammer technique using only stone-age tools, from selecting appropriate bones to extracting every gram of marrow.