Innovative problem solving by wild spotted hyenas

Abstract

Innovative animals are those able to solve novel problems or invent novel solutions to existing problems. Despite the important ecological and evolutionary consequences of innovation, we still know very little about the traits that vary among individuals within a species to make them more or less innovative. Here we examine innovative problem solving by spotted hyenas (Crocuta crocuta) in their natural habitat, and demonstrate for the first time in a non-human animal that those individuals exhibiting a greater diversity of initial exploratory behaviours are more successful problem solvers. Additionally, as in earlier work, we found that neophobia was a critical inhibitor of problem-solving success. Interestingly, although juveniles and adults were equally successful in solving the problem, juveniles were significantly more diverse in their initial exploratory behaviours, more persistent and less neophobic than were adults. We found no significant effects of social rank or sex on success, the diversity of initial exploratory behaviours, behavioural persistence or neophobia. Our results suggest that the diversity of initial exploratory behaviours, akin to some measures of human creativity, is an important, but largely overlooked, determinant of problem-solving success in non-human animals.

Figure 1.

(a) An image of the puzzle box apparatus used in the experiment. (b) A close-up image of the latch bolt that hyenas had to move laterally in order to access the meat inside the puzzle box.

Figure 2.

Average learning curve for successful wild hyenas when interacting with the puzzle box. The learning curve represents the mean ± s.e. work time for all individuals who were successful in a given trial. Trial 1 represents the trial in which an individual was initially successful, and may not be the first time an individual interacted with the puzzle box. Sample sizes in trials 2–22 varied because not all seven hyenas that opened the puzzle box multiple times were successful in every trial.

Figure 3.

Mean ± s.e. (a) exploration diversity, (b) work time (indicating persistence) and (c) latency to approach in the initial trial with the puzzle box for all individuals for whom these measures could be scored. Bars indicate whether an individual was ever successful in opening the puzzle box. Asterisks represent significant differences where *p < 0.05.

Figure 4.

Mean ± s.e. (a) exploration diversity, (b) work time and (c) latency to approach the puzzle box during the initial trial for focal hyenas sorted by age class. Asterisks represent significant differences where **p < 0.01 and ***p < 0.001.

Figure 5.

Mean ± s.e. exploration diversity across all trials for each individual hyena that participated in multiple puzzle box trials (n = 40). Individual hyenas are listed along the x-axis. Box colour and shape indicate whether the individual ever opened the puzzle box. Black circles, successful; white squares, unsuccessful.