Bats are valuable allies, well worth protecting. Worldwide, they are primary predators of vast numbers of insect pests that cost farmers and foresters billions of dollars annually and spread human disease. For example, in the United States, Little Brown Bats often eat mosquitoes and can catch up to 1,200 tiny insects in an hour. An average-sized colony of Big Brown Bats can eat enough cucumber beetles to protect farmers from tens of millions of the beetle's rootworm larva each summer. Large colonies of Mexican Free-Tailed Bats eat hundreds of tons of moth pests weekly. Bats play key roles in keeping a wide variety of insect populations in balance. Yet, they rank as North America's most rapidly declining and endangered land mammals. The largest known cause of decline is exaggerated human fear and persecution.