Are these animals of different species?
Yes, they are sheep and dogs.
     src        edge_attr  dst
0      0  to the right of   17
1      0  to the right of    6
2      0  to the right of   14
3      0  to the right of    3
4      0  to the right of   15
..   ...              ...  ...
112   19   to the left of   13
113   19  to the right of   20
114   20   to the left of   13
115   20   to the left of    1
116   20   to the left of   19

[117 rows x 3 columns]