In central Idaho, local hostility to wolves expresses itself on signs along the highway. Many residents don't like the wolves because the animals kill elk, livestock and pets. Martin Kaste/NPR hide caption

itoggle caption Martin Kaste/NPR

Mighty Mouse? Male Alston's mice use high-frequency songs to entice females. Bret Pasch/University of Florida hide caption

itoggle caption Bret Pasch/University of Florida

A female mosquito acquires a blood meal. This species, Aedes aegypti, carries and transmits the dengue fever virus. James Gathany/CDC hide caption

itoggle caption James Gathany/CDC