species	tail_length
mus_musculus	11.3
mus_musculus	10.6
mus_musculus	12.1
mus_musculus	9.5
mus_musculus	11.7
mus_musculus	10.8
mus_spretus	5.4
mus_spretus	5.6
mus_spretus	6.1
mus_spretus	4.9
mus_spretus	5.3
mus_spretus	4.6