Invaders, The

The infamous drug lord Pablo Escobar was notorious for smuggling cocaine, but perhaps less known for illegally importing exotic species to his personal zoo. Soon after Escobar's demise, the animals were left alone, and now, one of these species has invaded the Colombian countryside ' a herd of more than 30 giant hippos! Join Nat Geo WILD for an exclusive look at the so-called "cocaine hippos" and the battle to control this thriving African invader.

Giant swamp rats are taking over the U.S. and destroying fragile ecosystems from Maryland to Oregon. The rodent, known as nutria, is native to Argentina, but was introduced to the U.S. during a "get-rich-quick" scheme to farm the animals for their fur. Now there are 20 million in Louisiana alone, and Nat Geo WILD is on the front lines with experts trying to curtail the invasive species.

As many as 23 million feral pigs have taken over Australia, causing an untold amount of damage. These highly intelligent invaders are endangering native species, spreading disease, destroying farmland and even attacking people. They were deliberately introduced by people centuries ago; now it's up to locals to keep their populations in check. Scientists and citizens are resorting to a range of methods to defend their country against these "pigzillas."

Major cities in the United States are in the grip of an invisible invasion. More and more people are falling victim to one of mans oldest parasitic pests, one that lives in colonies hidden in our furniture and literally drinks our blood while we sleep: bed bugs. From apartments in New York to caves in Arizona, join researchers, entomologists and exterminators as they struggle to better understand bed bugs and find ways for us to survive the impending bed bug invasion.

A moose in the country is no big deal ' but a moose in a New York suburb is a recipe for disaster. At upwards of 6 feet tall and weighing more than ton, moose have a reputation as gentle, clumsy giants. But with large racks of antlers and sharp hooves, they can be dangerous. Nat Geo WILD examines why moose are invading the Northeast, infiltrating populated areas including regions just outside of New York City.

Coyotes are invading backyards across America. With sharp teeth, wily intelligence and a body built for speed, these formidable predators can adapt and survive in nearly any environment. They are a threat people as well as pets ' attacking a 19-year-old girl in Nova Scotia, stalking joggers in New Jersey and snatching a toddler right out of its sandbox in California. Worse yet, biologists have now uncovered a hybrid species that is larger and more aggressive ' the coywolf.