There have been many sightings and stories over the last few decades where it has been reported that monkeys have been seen making tools for various reasons. The stories have come from many different species of monkey and in many different parts of the world under different settings, for example some have been seen in their natural habitat and others are from lab work.
Chimpanzees and Tool Making
In 2007 in the Washington Post a story featured where it has been observed that chimpanzee monkeys have been tool making to use as weapons. The chimpanzees were fashioning spears made from sticks and other tools to kill their prey. These chimpanzees were using their hands and teeth for tool making and they were very good at it as well. It was stated that they tore off the side of branches to create the long stick, and peeled back the bark on one end to create the sharp spear. It was also stated that not only were they using their talents for the tool making but once the tool was created they were holding the spear in their hands in a "power grip" which was then used to kill other smaller mammals.
Tool Making and Macaque Monkeys
Another story details how macaque monkeys in a laboratory in Japan were reported to act in a similar nature as the chimpanzees by their use of tool making. These macaque monkeys were trying to grab food that was just out of their reach. In response the monkeys devised a utensil by tool making in which they could drag the food closer towards them to reach for the food. At this time it is rare to see macaque monkeys in the wild using tools or even tool making and so it can be argued that it was the effect of the lab and being around people that they learnt how to manipulate something by the use of a tool.
There are many other monkey species from around the world who have been reported to use tool making in the wild, and this only seems to be increasing as time goes on.