Science/Tech

Endangered Sierra Nevada Bighorn Sheep Released in Yosemite National Park

Known for their agility on rocky terrain and giant coiled horns, Sierra Nevada bighorn sheep have roamed western territories by the thousands before settlers arrived. Adult bighorn sheep, or rams, stand over three feet tall and can weigh up to 220 pounds; females, or ewes, weigh up to 155 pounds. Rams possess the trademark coiled horns; female horns are shorter and straighter. The coloration of bighorn sheep can range from dark brown to almost white; they also have a large white rump patch and a small, dark tail. The lifespan of a ram is about 10-12 years while ewes can live to be 17. Sierra Nevada bighorn sheep navigate through craggy surfaces with ease and adroitness, earning John Muir’s description as the “bravest of all Sierra Mountaineers”.

Unfortunately, disease and unregulated hunting brought by settlers caused a fast decline in their population, and bighorn sheep were officially listed as a federally endangered species in 2000 when their numbers dropped below a mere 100.

Since then, the population of bighorn sheep has made a significant increase to around 600. In the spring of 2015, a multi-agency effort was made to release two herds of the endangered species into Yosemite and Sequoia National Parks for the first time in over 100 years. From the Inyo National Forest, nine ewes and three rams were moved into the Cathedral Range of Yosemite National Park and seven ewes were moved to the Laurel Creek area of Sequoia National Park. This recovery effort required the capture of Sierra Nevada bighorn sheep on federally managed lands; the California Department of Fish and Wildlife staff and volunteers examined the health and safety of the bighorn sheep with the help of veterinarians, biologists, and staff from other agencies. Each animal received a radio collar and Global Positioning System (GPS) for tracking over the next couple years.

Bighorn sheep Yosemite National Park scenery

Yosemite National Park

The new homes of the bighorn sheep provide superb habitats with an abundance of foliage, distance from domestic sheep grazing grounds (to prevent potential disease transmission), and access to other Sierra Nevada bighorn sheep in the area. Needless to say, the new occupants of the area thrive off their excellent surroundings, as seen in the latest episode of Yosemite Nature Notes, filmed by Steve Bumgardner. Published on December 16th, the video features remarkable footage of the bighorn sheep as well as interviews with wildlife biologists and a unique re-introduction of the species to Yosemite National Park’s Cathedral Range.

To watch “Bighorn Sheep-Yosemite Nature Notes” click here.

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1 Comment

  1. wjchen@cox.net'
    Wei
    January 22, 2016 at 12:47 pm — Reply

    This is a wonderful news, thanks for sharing!!

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