The past four years have seen a tragic, record-breaking spike in the numbers of grizzly bears killed in conflicts with humans in the Greater Yellowstone Ecosystem. In fact, more than 70 percent of grizzly bear deaths in this region are now caused by human activity, and almost all are preventable. Most of these conflicts happen due to perceived interference with livestock, or encounters with elk hunters who leave behind gut piles and carcasses -- a highly attractive food source for grizzly bears.

Grizzly bears are a threatened species. That’s why the Humane Society of the United States and other groups have worked to restore protections for Greater Yellowstone Ecosystem grizzly bears through the courts, so we can keep them out of the sights of trophy hunters who seek to kill them solely for pleasure. But for this important American species to truly recover, we also need to reduce other causes of mortality, including human conflict.

To this end, our wildlife team has been working to refute common misperceptions about grizzly bears that states often use as an excuse to demand an end to federal protections and to open season on the bears. Last month, we published a groundbreaking report that shows claims of livestock losses caused by grizzly bears are vastly overblown. We also outlined humane, cost-effective and non-lethal alternatives to killing bears when livestock losses do occur.

Yesterday, we took our efforts to protect grizzly bears one step further. Joining with the Sierra Club, the Center for Biological Diversity, Natural Resources Defense Council, WildEarth Guardians, Wyoming Wildlife Advocates and the Western Watershed Project, we filed a legal petition with Wyoming and Idaho authorities to implement an easy, inexpensive and non-lethal solution to reduce conflicts with elk hunters – one that has proven highly effective: pepper spray.

Not unlike the pepper spray used to ward off human attackers, the bear spray is an aerosol pepper spray used to stop aggressive behavior in bears. It is widely available and used both in the United States and Canada, and studies show that it is far more effective than firearms at preventing human injury during bear encounters. In fact, users avoid any injury up to 98 percent of the time (compared to 50 percent for firearms) and the bear does not have to die.

Elk hunters encounter bears at especially high rates because the animals -- who are already facing declining food sources in their habitats -- are attracted to the carcasses the hunters leave behind. The fall hunting season also coincides with the period when bears are preparing to den down for the winter and have the highest need for calories. Bears shot in these situations are frequently mothers seeking food for themselves and their cubs, who cannot survive on their own.

Most Americans do not want to see grizzlies die, or worse, go extinct. Wyoming, Idaho, Alaska and Montana, the states that are home to these beautiful animals, would do well to adopt common-sense solutions like pepper spray. By doing so they can ensure that they, and their residents, will continue to enjoy the tourism dollars and other benefits that grizzly bears bring for decades to come.