Figure 1. Survival of C57BL/6N×BALB/c F2 hybrid male and female mice presented as intervals of natural lifespan. The lower limit of the lifespans, referred to as “Survival Curve A” in Table 2, was obtained by considering euthanization of animals as the same fate as natural death and the upper limit of the lifespans, referred to as “Survival Curve B” in Table 2, by considering euthanized animals as healthy upon removal (censored) and only animals that died of intrinsic causes were counted as deaths. Animals in the cohorts for behavioral assessment were included in the survival analysis until the time of their first test (7, 15, or 22 months of age). Timepoints are indicated by dotted vertical lines. Total number of animals: nmales=48, nfemales=51.