Gorillas can spontaneously clean their food before eating it, without first watching another animal to learn from them, an international team of researchers has found. Published in the journal PLoS ONE, the findings challenge the interpretation of recently published data that suggested that gorillas acquire food cleaning primarily by learning from others.
Gorillas appear to be born with an instinct to clean their food. Image credit: Skeeze.
Lead author Damien Neadle, from the University of Birmingham, and colleagues tested to what extent food cleaning behavior in a group of captive Western lowland gorillas (Gorilla gorilla gorilla) at the Wolfgang Kohler Primate Research Centre in Leipzig Zoo, Germany, relies on social learning processes.
The subjects were provided with clean and dirty apples.
When they were provided with dirty apples, coated with sand, all subjects showed evidence of food cleaning in at least 75% of trials.
Preferred cleaning techniques differed between individuals, four out of five of subjects expressed a behavior analogous to that reported in wild gorillas.
“In four of our five gorillas, at least one of the techniques for cleaning was similar to that observed in the wild,” Dr. Neadle explained.
“Given that these two groups are culturally unconnected, it suggests that social learning is not required for this behavior to emerge.”
“This fact does not discount the importance of social learning, but simply emphasizes the role of individual learning in the emergence of food cleaning behavior in western lowland gorillas.”
“Here, we argue that individual learning is responsible for the form of the behavior, whilst social learning possibly contributes to its frequency.”
“Rather than being a binary consideration of either cultural learning or not, behaviors like food cleaning, which can be propagated by shared learning but are also capable of being learnt spontaneously by individuals, could be deemed to be ‘soft culture’.”
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D. Neadle et al. 2017. Food cleaning in gorillas: Social learning is a possibility but not a necessity. PLoS ONE 12 (12): e0188866; doi: 10.1371/journal.pone.0188866
