Bighorn Sheep Declining in Tetons | Big Horn Basin Media

Mountain Goats Pose Potential Threat for Bighorn Sheep

Written by on May 1, 2017

Wildlife managers are concerned about population trends for mountain goats and bighorn sheep in the Tetons.

A biologist says the population of non-native mountain goats is growing prolifically in the Teton Range, while the number of native bighorn sheep is in noticeable decline.

According to an article in the Jackson Hole News and Guide, Wyoming Game and Fish Department biologist Aly Courtemanch said that over the past three years she has counted no more than 57 bighorns in the Tetons, a considerable drop from counts of 96 in 2008 and 81 in 2010. However, estimates of mountain goat numbers range between 60 and 80.

The exotic species was introduced by Idaho decades ago to be hunted. The first observation of mountain goats in the park was in 1977, but the goats weren’t known to be reproducing in the Tetons until 2008. In 2013 Grand Teton biologists told the News&Guide their estimate was 10 to 15 goats living in the park. That estimate grew in 2015 to between 20 and 40, but by 2016 the figure was up to 40 to 60 animals.

Courtemanch said that the fact that they saw almost as many goats as sheep is concerning. Teton Range goats have tested positive for strains of bacterial pathogens that can be deadly in bighorns, triggering potentially catastrophic pneumonia outbreaks.

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