The success of the invasive species often comes at the expense of the natives.
People used to scare their kids with stories of alligators in the sewers, growing up from baby 'gators brought up from Florida as souvenirs and then dumped as they grew big. But you really don't hear about a lot of alligator attacks on sewer workers.
In the Florida Everglades, sightings of some medium-size mammals are down as much as 99 percent and it's thought that pythons and other non-native constrictors are responsible.The National Park Service says 1,825 Burmese pythons have been caught in and around Everglades National Park since 2000. They believe that tens of thousands of them are living there. A recently captured Burmese python was 16' 5" long and weighed 156 pounds. How can there be so many? It becomes clearer when you look inside. This one contained 59 python embryos. With no natural predators scientists fear the pythons are disrupting the food chain and upset the Everglades' delicate environmental balance in ways difficult to predict. Presently they are causing mayhem in the Everglades where they are decimating native species, numbers of raccoons, opossums, bobcats and other mammals.
So please keep your pets on a leash.
"Give me your tired, your poor, Your huddled masses yearning to breathe free, The wretched refuse of your teeming shore. Send these, the homeless, tempest-tost to me, I lift my lamp beside the golden door!"
In the early 20th century, immigrants were, if not welcome, mostly tolerated. They provided an essential labor force to build a rapidly growing country. They were mostly poor people looking for a better life, and many of them had to sell all of their possessions and borrow money just to get here. They didn't travel first class.
Fourth class travel was often called "Steerage Class" because the passengers were crowded like cattle. But that was nearly a hundred years ago. Immigrants and the way they travel have changed drastically.
Instead of Europeans arriving by ship, today's immigrants are mostly Mexicans entering on foot or in vehicles.
But sometimes conditions aren't any better.
Recently, Mexican police found 513 people squeezed together in two trucks just outside Tuxtla Gutierrez, Chiapas - a painful 18-hour-drive away from the nearest US border.They were caught when the trucks sped through a vehicle scanner at a police checkpoint. After the incredible X-ray image came up on the screen, police gave chase, finding 240 people in one truck and 273 crammed into the other. The vacationers are being given spacious apartments before being repatriated to their home countries.