Most of the tools chimps use are biodegradable objects. Stuff like wood and leaves that rot away over time. However, they do use rocks to crack nuts. This leaves behind telltale evidence of chimp technology, which allows researchers to study it over time. This "chimp archaeology" has revealed that it hasn't changed a fat lot in the last 4,000 years ( whereas we humans have made huge strides since Noah's flood). Why is chimp technology in such a rut? Well, more chimp archaeology has revealed it may be because its very conformist.
Chimps typically live in cartloads. However, every so often a lady chimp leaves the group in search for a new home. This sort of immigration helps keep genetic diversity fresh amongst chimps; preventing any being born with an extra toe. These migrating females are typically adults, so have accumulated a whole lifetimes worth of know-how on making chimp technology.
Yet this chimp archaeology reveals that once they arrive in a new group they soon abandon their old way of doing things. Instead they soon learn the ways of their new group and use their technology instead. Even when the new method offers no real advantages over their old groups' technology.
These chimp archaeologists (also punily called " pan thropologists") examined the archaeology left behind by the nut cracking efforts of one group of chimps. Nicknamed the SoS group (or SoS cartload, as I prefer); the panthropologists found they used a lot more wooden tools than other nearby groups. However, they then observed some chimps from the SoS cartload migrating into another group. These migrants soon abandoned their old habit of using lots of wooden tools in favour of using more stone tools, like their new group.
This observation confirms something we've seen in captivity a fair bit; with new chimps introduced into a zoo soon adopting the ways of the local inhabitants. New chimps try to mimic the behaviour of high ranking individuals, presumably in an effort to earn favour with them. This sort of conformist behaviour can lead to the spread of seemingly useless practices. Like sticking grass in your ear.
However, chimps in captivity might not be the best source of information about how they normally behave. As such, this chimp archaeology is important for revealing that these factors could really be why chimp technology is stuck in a rut.
Our ancestors also found themselves in something of a rut for a long time. The earliest stone tools remained unchanged for almost a million years. Might this be because they also had a drive to conform, which could of quashed down any innovation? Something conformity something, joke about apple products.
Reference
Luncz, L. V., Wittig, R. M., & Boesch, C. (2015). Primate archaeology reveals cultural transmission in wild chimpanzees (Pan troglodytes verus). Phil. Trans. R. Soc. B, 370(1682), 20140348.
