After conducting a study on male bighorn sheep, Canadian researchers have successfully established a link between personality, survival, and reproductive success.
Denis Reale, a professor in the Department of Biological Sciences at UQAM and Canada Research Chair in Behavioural Ecology, says that the new study offers insight into personality differences in animals and humans, from an evolutionary perspective.
Since 1969, several teams of researchers have been studying this population of bighorn sheep in Alberta, Canada. They have collected considerable data over the years.
The researchers then conducted paternity tests to determine which rams were reproducing.
They point out that in a system like that of bighorn sheep where there is strong competition among the males for impregnating females, large size and high dominance status are normally key factors in a male's success.
Males usually attain these conditions in the prime of life, between 6 and 12 years, the researchers say.
However, the paternity tests showed that some young males manage to fertilize females.
The researchers also concentrated on the risk associated with participation in the rut-males can be injured or fall from a cliff in fighting.
Reale and his colleagues hypothesized that the young males that manage to reproduce would be the boldest and most combative, and analysis of the data confirmed it.
However, in exchange for sexual precocity and risk-taking, these rams often die younger than their more docile peers. The latter, instead, invest in the long term, breed later and reach an older age.
Based on their observations, the researchers came to the conclusion that their findings indicate a variation in the personalities and life histories of the population, with two extreme types: one that could be characterised as "live fast and die" and the other as "slow and steady wins the race".
Depending on their personality, the males managed to breed and to transmit their genes, but in different ways.
The study demonstrates that personality has a direct influence on the lifestyle of individuals.
A research article describing the study has been published in the Journal of Evolutionary Biology.