The Center for Biological Diversity, the Humane Society of the United States, and the Sierra Club sued the U.S. Fish & Wildlife Service (FWS) for missing its deadline to decide whether gray wolves in the northern Rocky Mountains warrant federal protection under the Endangered Species Act (ESA). The lawsuit follows a petition submitted to FWS seeking ESA protection for gray wolves in the Northern Rocky Mountains following the enactment of state laws in Idaho and Montana that legalized use of night vision scopes, strangulation snares, private contractors and other methods to kill wolves.