Washington: A new study has found that female mice with greater life expectancy are less active and less explorative than their fellow females with lower life expectancy.
Anna Lindholm, behavioral biologists from the University of Zurich, and her doctoral student Yannick Auclair investigated whether risky behavior can lead to premature death in animals - like it does in humans - by studying the behavior of 82 house mice.
They recorded boldness, activity level, exploration tendency and energy intake of female and male house mice with two different allelic variants on chromosome 17, thereby testing predictions of "life-history theory" on how individuals invest optimally in growth and reproduction.
According to this theory, individuals with a greater life expectancy will express reactive personality traits and will be shy, less active and less explorative than individuals with a lower survival expectation.
Female mice of the t haplotype, one of the two genetic variants on chromosome 17, are known to live longer.
The t haplotype in house mice is a naturally occurring selfish genetic element that is transmitted to 90 percent of the offspring by t carrying males.
Embryos that inherit a t copy from both parents, however, die before birth.
With his experiment, Auclair wanted to investigate whether there was a correlation between this selfish genetic element and the personality of the mice.
The researchers revealed that the longer-lived t haplotype females are less active than the shorter-lived non-carrier females.
They also consume less food, are less explorative and thus express reactive personality traits favouring cautiousness and energy conservation, as predicted by theory.
According to the research team, female mice with a longer life expectancy follow the strategy "live slow, die old" whereas those with a shorter life expectancy live according to the principle "live fast, die young".