As you might imagine, archaeologists have been studying the projectile point for a very long time; here are some of the lesser known findings of our research.
Little Known Fact Number 1: By and large, you can tell how old a projectile point is or where it came from by its shape and size.
Projectile points are identified to culture and time period on the basis of their characteristics. Shapes and thicknesses changed over time for reasons probably related to function and technology, as well as style within a particular group, but for whatever reason, generations of archaeologists are very happy they were made this way. Studies of different sizes and shapes of points are called point typologies.
In general, the larger, finely made points are the oldest points, and are called spear points, used as the working ends of spears. The middle sized, fairly thick points are called dart points; these are in between arrows and spear points, and they were used with an atlatl. Tiny points are the most recent, used at the ends of arrows shot with bows.
Little Known Fact Number 2: Archaeologists use a microscope and chemical analysis to identify scratches and minute traces of blood or other substances on the edges of projectile points.
On points excavated from intact archaeological sites, forensic analysis can often identify trace elements of blood or protein on the edges of tools, allowing the archaeologist to make substantive interpretations on what a point was used for. Called blood residue or protein residue analysis, the test has become a fairly common one.
In an allied laboratory field, deposits of opal phytoliths have been found on the edges of stone tools, which help identify the plants that were harvested or worked with stone sickles.
Another avenue of research is called usewear analysis, in which archaeologists use a microscope to search for small scratches and breaks in the edges of stone tools. Usewear analysis is often used in conjunction with experimental archaeology, in which people attempt to reproduce ancient technologies.
Little Known Fact Number 3: Broken points are more interesting than whole ones.
Lithic specialists who have studied stone tool breaks for decades can recognize how and why an arrowhead came to be broken, whether in the process of being made, during hunting, or an intentional or accidental break. Points that broke during manufacture often present information about the process of their construction. Intentional breaks can be representative of ritual or other activities.
Archaeologists love it when they find a broken point in the midst of the flaky stone debris (called debitage) that was created during the point's construction. Such a cluster of artifacts has just fistfuls of information about human behaviors.
Little Known Fact Number 4: Archaeologists sometime use broken arrowheads and projectile points as interpretive tools.
When an isolated point tip is found away from a campsite, archaeologists interpret this to mean that the tool broke during a hunting trip. When the haft portion of a broken point is found, it's almost always at a base camp. The theory is, the tip is left behind at the hunting site (or embedded in the animal), while the hafting element is taken back to the base camp for possible reworking.
Some of the oddest looking projectile points were reworked from earlier points, such as when an old point was found and reworked by a later group.
Little Known Fact Number 5: Some native cherts and flints improve their character by being exposed to heat.
Experimental archaeologists have identified the effects of heat treatment on some stone to increase a raw material's gloss, alter the color, and most importantly, increase the stone's knappability.Little Known Fact Number 6: Stone tools are fragile.
According to several archaeological experiments, stone projectile points break in use and frequently after only one to three uses, and few remain usable for very long.
Little Known Fact Number 7: Stone projectile point use is at least as old as the Middle Paleolithic Levallois period
Pointed stone and bone objects have been discovered on many Middle Paleolithic archaeological sites, such as Umm el Tiel in Syria, Oscurusciuto in Italy, and Blombos and Sibudu Caves in South Africa. These points were probably used as thrusting or throwing spears, by both Neanderthals and Early Modern Humans, as long ago as ~200,000 years. Untipped sharpened wooden spears were in use by ~400-300,000 years ago.
The atlatl, a device to assist in throwing spears, was invented by humans during the Upper Paleolithic period, at least 20,000 years ago.
See the Bibliography of Projectile Point Experiments for references