Mother Nature might have taken care of killing the non-native pest. The Florida Fish and Wildlife Conservation Commission says the state's unseasonably cold winter weather is believed to have killed up to 50 percent of the pythons.

Hardin said nine out of 10 pythons that scientists had been tracking with radio collars in Everglades National Park apparently died from the weather.
How do they assume that only 50% were killed when the next line says that 9 out of 10 died...