One side effect of globalization is the transplantation of various species from one part of the planet to another. They are brought over by accident, as pets, or as remedies for one problem before becoming the cause of another. However they get here, these animals’ environments do not come with them, and that includes their predators. So they proliferate, unchecked, competing with native species for food and sometimes even eating the native species themselves.
There are those who would argue that human beings, perched at the so-called top of the food chain as we are, are the most invasive species of all.
But humans aside, here are several species that pose a threat and are confounding efforts to check their numbers.
The python is well known to have invaded Florida and taken up residence in the Everglades, where it threatens native species and is great at hiding. Although no human deaths have been reported as recently happened in Canada—when a python escaped, climbed through a ventilation system and strangled two children—the serpents in Florida have decimated the ranks of bobcats, opossums, raccoons and other species.
Last year a team caught a mama carrying 80 eggs, underscoring the ability of these reptiles to take over the world.
Soon after, state wildlife officials put a bounty on their heads, proclaiming Python Challenge 2013 and offering prize money to those who killed the most pythons.
2. African Snails
Aficionados of the original Batman television series may remember the time that his sidekick, Robin, and a character named Venus are nearly devoured by a giant clam.
Well, this one is about as outrageous, only this is real life, not reel life. An invasion—a very slow one—has commenced of rat-sized snails that carry a parasite that causes meningitis in humans.
This African import has been eating its way through Florida’s stucco, plastic recycling bins, signs and more than 500 plant species. They apparently need all that food to produce up to 1,200 eggs over their nine-year lifespan and grow razor-sharp shells of calcium that can puncture tires. Wildlife officials fear they could also take out crops.
3. Northern Pike
Another voracious eater, the northern pike, threatens native fish, and the Kalispel Tribe is hard at work trying to stem their numbers. That is not as easy as it sounds, since the fish accumulate so many pollutants that they can only be eaten in extremely limited quantities, and are not recommended for women and children.
“Northern pike shouldn’t be thought of as a game fish anywhere in the [Columbia] basin,” said Deane Osterman, executive director of natural resources for the Kalispel Tribe. “They should be persona-non-grata and should be killed on sight.”
5. Asian Carp
The hallmark of this feisty fish is its penchant for leaping into the air, en masse, when a passing boat’s vibrations disturb the water they’re swimming in. The Asian carp, introduced in the 1970s to devour pond scum that menaced catfish, are now themselves a menace. Besides fish-slapping boaters with 20 to 40 pounds of flopping body weight, the Asian carp could threaten the $7 billion Great Lakes fishery industry, if the fish were to make it that far.
6. Feral Pigs
As ICTMN reported on August 19, feral pigs and their razor-sharp teeth have already taken over parts of Texas and are threatening to do so in at least 33 other states. These voracious hybrids of European hogs and domesticated swine are eating and reproducing their way through farmland and suburb alike.
“These animals, truly the ultimate omnivore, are an environmental and economic disaster that already causes over a billion dollars in damages every year,” said Alan May, the U.S. Department of Agriculture and Wildlife Services Director for New Mexico, to ICTMN.
The arrival of this Indo-Pacific Ocean native is a byproduct of the 1980s aquarium trade, according to The Christian Science Monitor. Most likely released into the ocean near southern Florida, they threaten coral reefs in the Caribbean and were recently discovered at ocean depths of 300 feet in the Atlantic by a team from the Hixon Lab at Oregon State University.
The venomously-spined lionfish eats anything smaller than it is, and is eating not only the food of the native species, but also the native species themselves, the Monitor reported on July 12.
“This data has confirmed for us that we have a problem there,” said the project’s lead scientist and a postdoctoral student at Hixon, Stephanie Green, to the newspaper. “This is the first time we’ve had a look at what the problem is in deep depths–it’s the next frontier in this study.”
“Genetic work has showed that the whole invasion began from a few releases,” said Green.
Although inroads have been made against them in shallower waters near the Florida coral reefs, the discovery of them in the deeper ocean means they could be regrouping there, out of reach.
8. Zebra Mussel
More annoying than harmful, this thumbnail-sized, invasive mollusk attaches in clusters to dock supports, clogs water intakes and smothers native mussels. It produces 100,000 to 500,000 eggs each per year, according to the Minnesota Department of Natural Resources, and its sharp shells can cut fishing lines and swimmers’ feet. The eggs develop into microscopic larvae and then form shells.