  Cultural learning is a unique human capacity essential for a wide range of
adaptations. Researchers have argued that folktales have the pedagogical
function of transmitting the essential information for the environment. The
most important knowledge for foraging and pastoral society is folk-zoological
knowledge, such as the predator-prey relationship among wild animals, or
between wild and domesticated animals. Here, we analysed the descriptions of
the 382 animal folktales using the natural language processing method and
descriptive statistics listed in a worldwide tale-type index
(Aarne-Thompson-Uther type index). Our analyses suggested that first, the
predator-prey relationship frequently appeared in a co-occurrent animal pair
within a folktale (e.g., cat and mouse or wolf and pig), and second, the motif
of 'deception', describing the antagonistic behaviour among animals, appeared
relatively higher in 'wild and domestic animals' and 'wild animals' than other
types. Furthermore, the motif of 'deception' appeared more frequently in pairs,
corresponding to the predator-prey relationship. These results corresponded
with the hypothesis that the combination of animal characters and what happens
in stories represented relationships in the real world. The present study
demonstrated that the combination of quantitative methods and qualitative data
broaden our understanding of the evolutionary aspects of human cultures.
