Top 4 Invasive Species in The United States

A detailed list of animals that have been deemed invasive in the United States.

Apr 21, 2023By Alex Guse
most invasive species united states

An invasive animal species is a non-native animal whose introduction can negatively impact the ecosystem and environment in which it is introduced. The animals on the list below may have been introduced to their respective ecosystems in differing ways; However, one thing is for sure, they have all caused severe trouble to the plants and animals before them. From insects to reptiles, these animals have topped the list of invasive environmental impacts in the United States.

4. Gypsy/Spongy Moth

Gypsy Moth

The Spongy Moth, formerly known as the Gypsy Moth, comes in at number four on our list of most invasive species in the United States, and for a good reason. They were first introduced in Boston around 1869 to recreate the silk industry of Eurasian countries. They came and haven’t left.

The reason these insects are considered invasive is their unique ability to migrate. The Spongy Moth and its larvae can produce little strands of silk picked up by the wind carrying the bug as far as a mile!

It isn’t just their use of the wind to migrate that makes them invasive; it is also their enormous appetites. Spongy moths eat nearly 300 types of foliage, and forests across the United States show the damage. The defoliation of trees and other fauna creates an environment where plants are highly susceptible to disease.

Because these animals have very few natural predators, they can migrate to new areas, eat everything, breed and continue to the next food source.

While these insects are attacking our forests, the next creature on our list is invading our urban areas.

3. European Starling

european starling

The European Starling is an interesting invasive species, as the way it was introduced into the United States is contested. The mainstream consensus was that a man, Eugene Schieffelin, wanted to introduce every bird that was mentioned in the works of Shakespeare. He then let 100 Starlings go into central park, where they began their reign of destruction.

The European Starlings love fruit and grains and have caused an estimated 800 million dollars of damage to the agriculture industry. Their love for these foods has brought them from rural farms into urban communities foraging in garbage-filled areas.

The avian also is a nuisance to residential areas due to their nesting tactics. The Starling will nest in any crevice possible, including ventilation into houses, wood piles, and pretty much anywhere in your garage. The nesting technique and materials used causes loads of structural damage and can become a fire hazard.

Between what they eat and where they lay their eggs, these invasive birds are destroying farms and homes across the United States.

2. Feral Pig

feral pig

The feral Pig is number two on our list and the second most famous herald of environmental destruction.

European settlers and explorers first brought them over as a food source. Sometimes ships would leave the pigs on land if they did not have enough feed. This led to a boom in the feral pig population, with another jump in the 1930s when wild boars were released for hunting.

Currently, there are an estimated nine million feral pigs across the United States, with 1.5 million residing in Texas, Texas being the hardest hit by these invasive mammals. It is estimated that 1.5 billion dollars worth of damage to the agriculture industry (52 million in Texas alone) can be attributed to the swine.

There are multiple reasons why these animals are so destructive. First is their appetite and ability to use their acute sense of smell to find the food they want. The pigs will sniff out said meal and then begin a process called rooting, where they dig many holes.

This is destructive to the soil and hinders farm equipment's ability to till, plant, and harvest in the area. The pigs also disturb the water quality with their feces. There is no solution to curbing the species as they produce faster than we can hunt them.

With no end in sight, the Feral Pig is here to stay, which means the invasion and destruction live on.

1. Burmese Python

python 3

Topping our list is the Burmese Python which has taken over the Everglades and much of Florida. These animals were first introduced to the United States as exotic pets, but when they started to become too large (up to 20 ft long), people began releasing them into the wild.

In the early 2000s, about 50,000 pythons were brought into the area as pets and were soon released into the wild. Because of their enormous size, they have very few predators willing to eat them.

They eat various animals, from small mammals to birds, and eradicate the local population.

The fewer bug-eating mammals there are, the more mosquitos inhabit the area, which means the risk of disease-carrying mosquitoes transmitting a disease to humans has skyrocketed.

The problem with curbing the population is pythons breed so quickly and are so sneaky it's hard to do something about them. The south Florida Water Management District has created a program to hire trappers to capture and euthanize this invasive reptile humanely; they even go so far as to hold contests each year to see who can capture or kill the most.

The Python is dangerous to humans, has destroyed the ecosystem it was introduced to, and wiped out most of the small mammal population in the Everglades.

These are the reasons that the Burmese Python lands at number one on our most invasive species list.

Alex Guse
By Alex Guse

Alex is the proud owner of Chester the puggle (beagle pug mix); his first dog was Zion, an Australian shepherd, which translated into a love for animals at an early age. He has since owned many pets, from dogs to reptiles and everything in between. His true passion for animals comes from being an outdoorsman. He finds that nature is where knowledge and respect for wildlife are paramount!