London - The great apes can remember events that happened years ago just like men and women do, researchers have found.
As with humans, a reminder of something in the distant past can jog the memories of chimps and orangutans.
Scientists took a group of apes and reconstructed a series of experiments conducted three years previously in which they had had to find hidden tools that could be used to reach food.
Faced with the same set up of rooms and boxes in which the tools were concealed, the apes immediately knew what to do. It took them only five seconds to find the tools.
Another group of apes which had not had the previous experience were left confused.
A second study showed chimps and orangutans could remember a single tool-finding task carried out two weeks earlier.
The complexity and speed of the apes’ recall ability was unexpected, said the scientists, whose findings appear in the journal Current Biology.
Study leader Dr Gema Martin-Ordas, from Aarhus University in Denmark, said: “I was surprised to find out not only that they remembered the event that took place three years ago, but also that they did it so fast.
“It shows that they were not just walking around the rooms and suddenly saw the boxes and searched for the tools inside them. More probably, it was the recalled event that enabled them to find the tools directly.”
The chimps and orangutans had participated in numerous past experiments with the same team of researchers, the scientists pointed out. Yet they were able to distinguish between similar past events involving the same tasks, locations and people. This was said to be a crucial finding.
Dr Martin-Ordas added: “Our data and other evidence challenge the idea of non-human animals being stuck in time.” - Daily Mail