Table 1. Frequency of observed maternal behaviors in inbred and reciprocal hybrid mothers.
| BEHAVIOR | C57BL/6 | BALB/c | F (1,50) | P-value | B6xC | CxB6 | F(1,75) | P-value |
| Arched-back nursing | 0.312±0.025 | 0.158±0.021 | 25.049 | 0.001 | 0.363±0.021 | 0.416±0.020 | 3.392 | n.s. |
| Blanket nursing | 0.270±0.028 | 0.428±0.028 | 15.763 | 0.001 | 0.206±0.024 | 0.172±0.018 | 1.357 | n.s. |
| Licking/grooming pups | 0.137±0.007 | 0.045±0.003 | 150.853 | 0.001 | 0.130±0.006 | 0.091±0.004 | 30.306 | 0.001 |
| Self grooming (in nest) | 0.014±0.002 | 0.019±0.003 | 1.731 | n.s. | 0.022±0.002 | 0.026±0.002 | 2.498 | n.s. |
| Sniffing nest | 0.029±0.003 | 0.012±0.001 | 31.594 | 0.001 | 0.007±0.001 | 0.009±0.001 | 2.672 | n.s. |
| Self grooming (out of nest) | 0.029±0.007 | 0.026±0.003 | 0.128 | n.s. | 0.031±0.002 | 0.034±0.003 | 0.698 | n.s. |
| Sniffing cage | 0.052±0.004 | 0.067±0.006 | 3.853 | n.s | 0.071±0.004 | 0.073±0.004 | 0.090 | n.s. |
| Eating | 0.079±0.005 | 0.119±0.007 | 21.747 | 0.001 | 0.085±0.005 | 0.083±0.004 | 0.088 | n.s. |
| Carrying pup | 0.001±0.000 | 0.000±0.000 | 6.683 | 0.013 | 0.000±0.000 | 0.000±0.000 | 0.947 | n.s. |
| Moving pups | 0.002±0.000 | 0.006±0.001 | 17.920 | 0.001 | 0.001±0.000 | 0.002±0.000 | 0.383 | n.s. |
| Nest Bulding | 0.012±0.002 | 0.010±0.001 | 0.506 | n.s. | 0.007±0.001 | 0.006±0.001 | 0.187 | n.s. |
| Sniffing pups | 0.010±0.001 | 0.012±0.001 | 0.786 | n.s. | 0.005±0.001 | 0.010±0.001 | 17.214 | 0.001 |
| Drinking | 0.015±0.002 | 0.021±0.002 | 4.021 | n.s. | 0.022±0.001 | 0.020±0.002 | 0.832 | n.s. |
| Rearing | 0.006±0.001 | 0.012±0.001 | 9.479 | 0.003 | 0.006±0.001 | 0.007±0.001 | 1.193 | n.s. |
| Digging | 0.016±0.002 | 0.039±0.005 | 15.640 | 0.001 | 0.014±0.002 | 0.015±0.002 | 0.154 | n.s. |
| Carrying tail | 0.006±0.001 | 0.008±0.002 | 0.778 | n.s. | 0.002±0.000 | 0.003±0.001 | 1.133 | n.s. |
| Climbing | 0.008±0.002 | 0.006±0.002 | 0.884 | n.s. | 0.006±0.001 | 0.003±0.001 | 3.092 | n.s. |
| Arched-back nursing (<half litter) | 0.000±0.000 | 0.001±0.000 | 1.207 | n.s. | 0.001±0.000 | 0.000±0.000 | 2.243 | n.s. |
| Licking/grooming pups (<half litter) | 0.000±0.000 | 0.001±0.000 | 1.859 | n.s. | 0.000±0.000 | 0.000±0.000 | 0.057 | n.s. |
| Blanket nursing (<half litter) | 0.000±0.000 | 0.004±0.004 | 1.337 | n.s. | 0.001±0.000 | 0.001±0.001 | 0.095 | n.s. |
| Sleeping | 0.000 ± 0.000 | 0.011 ± 0.038 | 7.989 | 0.007 | 0.017±0.003 | 0.026±0.004 | 2.683 | n.s. |
Mean frequencies (± SEM) of an ethogram of twenty-one observed maternal behaviors for C57BL/6 vs. BALB/c (left) and B6xC vs. CxB6 (right) mothers. Behaviors were scored once each minute for two non-contiguous hours each day from postnatal day 1 to 7. Statistical significance was calculated by univariate ANOVA and significant differences (P<0.05) are indicated in bold.