index,animal_id,sex,age,weight
1,31210_1,f,12,6.7
2,31210_2,m,12,6.9
3,31210_3,f,12,6.8
4,1809_1,m,11,5.9
5,1809_2,f,11,5.8
6,1809_3,f,11,5.4
7,1809_4,f,12,6.6