Bighorn Sheep: Is 'Personality Type' Linked To Longevity, Offspring?

Coltman, a U of A biology professor, is part of a team that traps the animals in a plywood enclosure on a mountaintop in the Rockies. He and the research team are trying to figure out if personality type has anything to do with how long a mountain sheep lives or how many offspring it produces.

The extreme ends of the personality measurement are bold and submissive. For example, with the younger male mountain sheep, a typical bold personality will try and steal away a ewe from the older dominant ram. Coltman equates that to a "live fast, die young" mentality seen regularly in the human world.

The animal is given a grade for personality based on how big a fight it puts up when researchers try and get its weight and measurements and Coltman says carrying out a personality profile can be dangerous. The average ram weighs 125 kilograms, but while some captured rams and even ewes put up a fight, Coltman says others are complete pussycats. "With some ewes you just put your hand on their head," said Coltman. "They just sit back on their bums and you can measure and weigh them; it's that easy."

But with others, the research doesn't come that easy. "We were filled with dread when one ram we nicknamed 'Psycho' turned up in a trap," said Coltman. "Year in and year out Psycho's reaction was the same. He tried to kill us."

The Ram Mountain trap-and-release study was originally organized close to 40 years ago to monitor the growth, health and population of bighorn sheep. Coltman is co-author of a recent paper on animal personality published in the Journal of Evolutionary Biology.