California biologists explain.

Add Yahoo as a preferred source to see more of our stories on Google. FILE: Tortoiseshell butterfly pictured at close range. (Russ Aguilar/500px/Getty Images) On Mother's Day, the thick blanket of ...

Why Do Monarch Butterflies Swarm? Monarch butterflies, like other butterfly species and birds, must migrate to warmer climates during the cold winter months. Monarch butterflies are unique because ...

A common thought experiment posits that a butterfly flapping its wings in Brazil can, over time, lead to a chain of events that sets off a tornado in Texas. It seems this old saw may be more true than ...

Butterflies are some of the most beautiful insects in the world. With so many different species and variations, butterflies are a marvel to behold. Now, imagine seeing a massive monarch butterfly ...