Monkeys plan ahead
Orangutans and bonobos seem to be able to plan ahead in a similar way to humans. As researchers from the Max Planck Institute for Evolutionary Anthropology in Leipzig observed, the great apes store useful tools that they might later need when gathering food. Josep Call now assumes that this ability developed more than 14 million years ago, when, according to the theory of evolution, the developmental strands of the two species of monkeys separated. Until now, scientists had only attributed the cognitive ability to plan ahead, that is, the ability to anticipate needs in the future.
Call and his colleagues hung a bottle filled with juice in front of the monkey cage and taught five bonobos and five orangutans each from the Leipzig Zoo to use a hook to reach the bottle. Later, the monkeys could choose one tool from useful and less useful tools and take it to a waiting room. After an hour, the great apes were allowed back into their cage and, if they had brought the right tool with them, could pull the reward towards them.
Although not all ten monkeys completed the task, the researchers believe that the test results provide evidence of the monkeys' anticipatory actions. After all, the female orangutan Dokana appeared from the waiting room almost every time with the right tool.
The researchers were able to confirm their test results with another experiment. Even though the monkeys slept one night during the experiment, they brought the tool with them the next day. Monkeys unexperienced with the experiment were significantly less likely to carry tools, even though they received rewards for carrying both useful and useless tools. Call was therefore able to rule out that the animals didn't like to carry the tool around with them as a toy anyway.
In further experiments, Call and his co-workers want to investigate how far ahead the monkeys can plan.
