This discovery is quite interesting! It baffles me that some people still do not believe in evolution and that humans and chimpanzees evolved from the same ancestor. Anyway, chimpanzees are incredible creatures, and anyone can clearly see how much in common humans and apes have.
As you can see in this video, the chimpanzee clearly understands the strategy of using a rock to open the nut. It is obvious that the chimpanzee connects logical steps to achieve the end result. Can one really deny the high degree of intelligence of this creature and not see that it is the primitive beginnings to our own intelligence?
There are many instances of chimpanzees as well as other primates using other tools. For example, chimpanzees strip branches of their leaves, stick them in termite holes, pull them out, and eat the termites stuck on the stick. Another documented study revealed how one genius can pass on behaviors to other individuals. (Please forgive me Dr. Sussman, but I have forgotten the name of the female!) In Asia, people would feed the macaques rice, but the monkeys found it hard to distinguish rice from the sand. One female grabbed a handful of rice plus sand and threw it in a nearby body of water. The rice floated while the sand sank. Eventually, the rest of the colony acquired this learned behavior, and similar to the article, the learned behavior was absent in males, specifically the older ones.
But what concerns me is the issue of chimpanzees eating meat. They mainly eat fruits, vegetables, and nuts. Occasionally, they will eat meat, but several researchers believe it is because of the encroachment of their land as well as the loss of resources. These reasons also lead to heightened violence/aggression. A couple of incidents have been recorded of colonies “warring” with each other and of males hunting colobus monkeys. In this article, the resources must be so depleted that the chimpanzees have been hunting for so long that they had to figure out a way to make it easier. Could we assume that chimpanzees will be hunting in packs with tools strategically?
Finally, I believe your final questions (Is not the ability to make tools one of the key ways to distinguish between humans and animals? What would it take a chimpanzee to do before we could consider it conscious?) really address the issue of theory of mind. Do chimpanzees demonstrate theory of mind? Well, there have been documented incidents of chimpanzees (and other monkeys) performing human-like behaviors such as deception.
For example, zoo researchers showed one chimpanzee that a banana was hidden behind a rock. When all of the apes were let back in, this one chimpanzee ran to the spot and tried eating the banana. But, the other chimpanzees also wanted some, and the banana was split among many. They redid the experiment, but this time the selected chimpanzee ran to a different spot with no banana. While the others were busy, the selected chimp went to the hidden spot and ate the banana by himself. What does this scenario tell us? Well, obviously, this animal understands the difference between self and others. I would call him a selfish bastard…the fact that he would deliberately deceive the others by leading them somewhere else.
There is no denying that chimpanzees understand “self.” Besides the multiple studies, I do know that chimpanzees can recognize themselves in mirrors. So, what really separates humans from chimpanzees or better yet animals? It is not theory of mind (or conscious) or emotions because chimps clearly demonstrate these behaviors. Language? Well, dolphins also clearly exhibit this behavior. So what is it really? It seems for right now, it is just a degree of intelligence and capability with given physical features. People (like the ones who don’t believe in evolution) need to stop thinking that humans and animals are separate. It is a matter of the evolution race.