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Hyena Problem Solving - Necessity is the Mother of Innovation

By Dave Armstrong - 08 Aug 2012 19:15:0 GMT
Hyena Problem Solving - Necessity is the Mother of Innovation

Hyena family in the Serengeti; Credit: © Shutterstock

Innovation is the life-blood of the problem solving animal. While some make do with inherited ability and long-term survival, humans are among those species that have adaptability in the short-term, with behavioural traits that seem to have served well. What makes animals innovational, though?

The first non-human to be faced with experimentation on its diversity of initial exploratory behaviours is... the spotted hyena. Get over it!

You're surprised that it's not a dolphin, ape or whatever? Today's Proceedings of the Royal Society B has a wonderful paper entitled, Innovative problem solving by wild spotted hyenas, which explains how we resemble and differ from animals in our problem-solving.

Sarah Benson-Amram and Kay E. Holekamp believe differently in Michigan State University. Using your resources better or finding new ways to exploit them is the key to a species such as the hyena (Crocuta crocuta).

To understand how variation within the species affects innovative tendencies is poorly enough understood in humans. For the hyena, a human infant experiment was presented in that they were investigated as follows:

The novel puzzle involved reporting on how diverse the individual's behaviours were and then comparing this diversity with their eventual success, or lack of it. Persistence and neophobia (avoidance of novel stimuli) were also examined as the study progressed. Two neighbouring clans from the Masai Mara were used, identified by unique spot patterns/ear notches.

A hyena approaches the puzzle box apparatus used in the experiment

Credit: © Proceedings of the Royal Society B

Above: A hyena approaches the puzzle box apparatus used in the experiment

A close-up image of the latch bolt that hyenas had to move laterally in order to access the meat inside the puzzle

Credit: © Proceedings of the Royal Society B

Above: A close-up image of the latch bolt that hyenas had to move laterally in order to access the meat inside the puzzle

This box of welded steel (Have you seen those gnashers?) was big enough for a hyena to poke his head inside to find raw meat. A steel bolt had to be slid across to swing the door open, using mouth or front paws. Subjects could drag, overturn and flip the box in the air, and they did! Each member of the clans was allowed to participate as far as possible and "team efforts," were possible in a sort of Hyenolympic athletic event.

In fact 88 lone hyenas and 329 group trials were the sum total of the experiment, perhaps reflecting the species' affinity for clan effort. 1-30 trials per hyena were allowed and 18 individuals performed at least 8 times. 14.5 % of 62 individuals opened the puzzle box, 7 individuals managing it more than once. The individual variation was from zero exploratory behaviour to a genius who averaged >3 behaviour types per trial. A lot of success was associated with this diversity, as you might expect.

The vital role of exploratory diversity in problem solving seems well supported by this research, to which any wild hyena would be naive. Adults proved more neophobic than juveniles. Persistence did not help in problem solving and sometimes inhibited the learning or problem solving. Alternative solutions were necessary for many hyenas and of course the adult neophobia didn't help. Repetition helped a lot with speed of solving the problem, as learning too, was rapid.

Less exploratory behaviour was exhibited later in experiments as experienced individuals quickly reached the reward. Age, sex, social rank and individual differences were recorded. Like teenagers, the juveniles had more free time to spend on their exploratory behaviours. However strength and physical ability must have influenced the result and acted against these young, smaller animals. Age itself failed to show correlation with their problem-solving success.

Social problems are solved quickly by hyena clans, but trial and error learning seems limited to just 14-5% of successful participants. A steep, smooth learning curve would have indicated insight learning, but this shallow jagged curve (seen in the graphs within the paper) proves a largely trial and error solution was adopted for this problem. Only 7% of wild vervet monkeys (Cercopithecus aethiops) solved similar problems, despite a similar social set-up.

The neophobia of wild animals could well account for this lack of success. A large brain can respond flexibly in novel situations simply by increasing the variety of response. Human creativity is now tested in the same way, which probably means that we surely have advanced just a little from our ancestral tree shrew.

Credit: Proceedings of the Royal Society B

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