Stephen Vantassel

A coyote hunts for small mammals in the tall grass, October 2008.
Vince O'Sullivan/FLICKR (CC BY-NC-ND 2.0)

About a dozen states – including Montana and Wyoming – are allowed to use a controversial device called the M-44. Advocates say it’s an important tool to protect sheep from coyotes. Critics call it a ‘cyanide bomb’ and say it’s too risky for humans and pets. Now, several environmental groups are pushing to ban them at the state and federal level.