"Scientists have waited for years for this moment. They are hoping that the extended, freakishly bitter cold just might accomplish what trappers have been unable to do: thin the population of pythons and other invaders running roughshod over the fragile environment and native species. Or at least slow their explosive growth."
The same article quotes University Florida Wildlife scientist Frank Mazzotti saying, "Today has been what I would consider a game changer...The pythons are going to be stunned by this kind of weather."
Other articles report 50% of the Burmese Python found were dead, describe the invasive Green Iguana as falling out of trees, and state that many invasive freshwater fish have died.
The cold snap undoubtedly brought about a die-off of individual animals that were exposed to the cold but some individuals will have been in shelters where they would be protected from the cold. They may have learned how to survive the cold weather. But, some of them, maybe just a few, have a physiology that allows them to better withstand the cold. These snakes will survive, reproduce, and leave offspring that are also able to survive cold snaps. Overtime the populations of invasive constricting snakes will adapt to the local climate that includes the occasional cold front that sags into southern Florida. Just as bacteria become resistant to antibiotics, snake populations will become resistant to cold. If the Burmese Python, African Python, Boa Constrictor populations are large enough they too will likely become cold resistant. Natural selection works this way. It should not be a surprise to any biologist.