The Pushing Match

[bobbin]

Wow, I've seen primates using twigs to catch insects up close and in person, but never even heard about them making something like a spear. How do they sharpen the tip? Have they been doing this for a long time, or have they learned by observing humans?

They use their teeth to trim the end into a point. No one can say how long they have been doing it or if they learned from observing humans, but I think the real importance of the finding was that it demonstrates they can understand the concept, which pushes back the barrier for use of custom tools massively.
IIRC the oldest definite evidence for a spear is from 400000 years ago, so that alone already pre dates modern humans by a huge amount of time.

Link to the research paper concerning tool use by chimpanzees.

It's very simple to make/use.

And effective, tools do not get used for as long as the spear has without being good at what they do.