| Sample | M3 | M31: non vocalized | M32: vocalized | |||||||||||
| Age | Nb | min | mean | max | SD | Cf.var | min | mean | max | SD | min | mean | max | SD |
| 7½ | 22 | 5.4 | 13.2 | 21.1 | 3.8 | 29% | 4.9 | 15.7 | 23.1 | 5.0 | 4.7 | 10.7 | 20.7 | 3.9 |
| 8½ | 22 | 8.7 | 18.6 | 27.2 | 5.0 | 27% | 7.3 | 22.7 | 35.3 | 7.0 | 8.4 | 14.4 | 22.9 | 4.0 |
| 9½ | 26 | 14.0 | 19.4 | 28.5 | 4.0 | 21% | 13.5 | 23.0 | 40.0 | 6.1 | 10.0 | 15.8 | 30.0 | 4.0 |
| 10½ | 22 | 14.0 | 20.9 | 32.9 | 5.0 | 24% | 15.0 | 25.4 | 37.5 | 6.3 | 8.4 | 16.4 | 28.4 | 5.3 |
| 11½ | 28 | 13.5 | 22.0 | 29.9 | 4.5 | 21% | 13.8 | 26.7 | 35.3 | 6.3 | 8.8 | 17.3 | 25.7 | 4.6 |
| Total | 120 | 5.4 | 19.0 | 33.0 | 5.3 | 28% | 4.9 | 22.9 | 40.0 | 7.0 | 4.7 | 15.1 | 30.0 | 4.9 |