Are the animals of different species?
No, all the animals are horses.
    src        edge_attr  dst
0     0  to the right of    9
1     1   to the left of    2
2     1  to the right of    7
3     1   to the left of    5
4     2  to the right of    1
5     2  to the right of   12
6     2  to the right of    9
7     3  to the right of   12
8     3  to the right of    6
9     5  to the right of    1
10    5  to the right of    9
11    5  to the right of   12
12    6   to the left of    3
13    6  to the right of    7
14    7   to the left of    1
15    7   to the left of    9
16    7   to the left of    6
17    8   to the left of    9
18    9   to the left of    2
19    9  to the right of   11
20    9   to the left of    5
21    9  to the right of    8
22    9   to the left of    0
23    9  to the right of    7
24   11   to the left of    9
25   12   to the left of    3
26   12   to the left of    5
27   12   to the left of    2