If you only read one long article this week, make it Burkhard Bilger's jaw-dropping "Swamp Things" in the current issue of the New Yorker. It's about how Florida accidentally became home to thousands of non-indigenous "exotic" creatures. Many started off as domestic pets and were let go when they got too big. Others were smuggled into the state to cater to a novelty-obsessed local market. Some were displaced many miles during Hurricane Andrew in 1992.
The outcome is that since 1994 the Florida Everglades have been home to a growing population of Burmese pythons. They were a few inches long when they were bought as pets. They can now grow to twenty feet and are almost-impossible to capture. They reckon that there could be 140,000 Burmese Pythons in the Everglades. This would be disturbing enough on its own but the last section of the article is about the arrival of the Nile Monitor. This six foot lizard, which is described as "omnicarnivorous", can out-run a man and is known to hunt in packs. Thanks to the canals linking the swamp with the town they have taken up residence on the lawns of a suburban community called Cape Coral.
It's a brilliant feature. The line that stays with you is a quote from one zoologist commenting on this alien invasion: "it's time to stop studying these things and start killing them".