Fig. 1: Co-occurrence relationship of the animals. In this figure, the size of each label (e.g., dog or rabbit) represents the sum of the frequency of an animal that appeared co-concurrently.

Each link between two labels represents a co-occurrent pair of animals, and the thickness of the links was adjusted by relative frequency. The labels with an asterisk (*) represent integrated categories of low-frequent animals. For example, ‘*bird’ contains words such as ‘swan’ or ‘cuckoo’ that appear at a lower frequency, and it does not include ‘chicken’ or ‘crow’ appears frequently (see section: The occurrence of animals in Methods; and also see Supplementary Table S3 for the full list). Since Fig. 1 was informative, and so we then extracted the pairs of animals with a high frequency (Fig. 2. (a) n > 10; Fig. 2. (b) n > 14).