September 16, 2009

Study looks at sheep personality variants

Canadian scientists say they have completed a study that links personality, survival and reproductive success in male bighorn sheep.

The researchers, led by University of Quebec at Montreal Professor Denis Reale, said their findings not only advance the knowledge of bighorn sheep, but also offer insight into personality differences in animals and humans from an evolutionary perspective.

Since 1969, several teams of researchers have been studying a population of bighorn sheep in Alberta, Canada. Reale and his colleagues focused on data concerning the animals' personality. Initially, the team identified the rams in terms of boldness and docility. They then conducted paternity tests to determine which rams were reproducing.

The study showed, as expected, young males that manage to reproduce are the boldest and most combative. However, in exchange for sexual precocity and risk-taking, the study showed those rams often die younger than their more docile peers. The latter, instead, invest in the long term, breed later and reach an older age, the scientists said.

The researchers said their findings indicate a variation in the personalities and life histories of the population, with two extreme types: one that could be characterized as live fast and die and the other as slow and steady wins the race.

The study, the researchers said, demonstrates personality has a direct influence on an individuals' lifestyle.

The findings appear in the Journal of Evolutionary Biology.