Written for The Jasper Fitzhugh.
|NIKI WILSON – On Science|
|July 04, 2013|
Revised to amend error July 10th.
Somewhere in the foothills of Caw Ridge, about 20 kilometres northwest of Grande Cache, Alta., a nannie goat is ramming another with her horns, or maybe giving her a little kick.
“Goats are the most aggressive hoofed animal in the world,” says Dr. Steeve Côté, professor of ecology at Université Laval. He’s been studying the goats at Caw Ridge for the better part of two decades, and says individual goats have the most fights per hour of any species. Aggression is predominantly between nannies. “The males are cool, but the females are nasty,” says Côté.
A desire to understand this aggression was one of the reasons Côté first started studying the Caw Ridge goats. Since then, his research has revealed that the low reproductive rate and harsh environment that contribute to female goat aggressiveness may also make them more vulnerable to disturbance from human activity.
Côté says nannies don’t reproduce until they are four or five years old, compared with other herbivores their size (deer or sheep) that have young around two years old. This is exacerbated by the fact that the females often take reproductive breaks. “Only 60 per cent of the females are producing each year,” says Côté. In recent years it’s been even less. “The population is going down.”
Côté has been trying to figure out why numbers are declining. The Caw Ridge population was one of the two biggest in the province outside of national parks. However, it is now only a thrid of the size it was five years ago. Human activity in their habitat may be a contributing factor.
Take for example their sensitivity to helicopter traffic. In a paper published last month, Côté suggests that after 40 years of exposure to helicopter traffic, the Caw Ridge goat population still shows few signs of habituation. Helicopters flying lower than 500 metres often send goats running toward escape terrain (like cliffs) where, depending on the frequency of flyovers, the goats may stay on alert for hours. This disrupts their eating, mating and resting.
As a result, Côté recommended 1,500 metres as the minimum horizontal distance helicopters should keep between them and goat habitat. This was the distance at which Côté observed only a light response in goats, if any at all.
Côté’s research has also shown goats to be sensitive to all-terrain-vehicle (ATV) traffic, which has increased dramatically in the Caw Ridge area since the mid-1990s. In recent years, about 400 people a summer visit the area on their ATVs. Speeds greater than 35 km/h result in the greatest disruption to goats.
Côté says that human disturbance from helicopters and ATVs doesn’t affect all animal species the same way. A high reproductive rate in some species may compensate for the disruption. However, as goats are slow reproducers, and are generally sensitive to start with, the impacts are greater.
Goats can habituate to people, says Côté, but it’s uncommon for them to do so. He only knows of three populations where this has occurred, and they are all in national parks. The Mount Kerkeslin goat lick here in Jasper National Park is one of them. In all three cases, goats are frequently exposed to people, but there is no industrial activity associated with the exposure.
The Caw Ridge Project will continue this summer, with its researchers collecting data and insights valuable in understanding and managing goat populations throughout the province. If recreationalists and industrial users heed Côté’s advice, the Caw Ridge goats may have a chance of kicking and fighting their way into the future.