5 invasive species you can see every day in the United States

Among the many challenges facing our environment in the modern world, the increasing prevalence of invasive species is being discussed more and more every day.

Invasive species are defined as organisms that arrived in an environment from which they did not originate and thrive despite it all, upsetting the delicate balance of their new home. This can be very destructive to local ecosystems, often leading to the reduction or even extinction of many populations of native species.

If it is true that some level of invasiveness is natural, after all, how else would species spread? – it is also no coincidence that the number and impact of invasive species has exploded over the past two centuries.

We humans have managed to build a hugely interconnected world, where worldwide travel and trade happens every day.

Unfortunately, it has also made it extremely easy for some species to hitch a ride and spread. far beyond their native ranges and wreak havoc on the unprepared ecosystems in which they find themselves.

Some most famous examples include cane toads in Australia, reticulated pythons in the Everglades and zebra mussels, well… everywhere.

However, these are examples of very egregious and well-known invaders. It is important to know that just because an invasive species is not obvious does not mean that it is not. just as a destroyer. In fact, many of the more inconspicuous species are also the most successful, aided by the much smaller spotlights shone upon them.

This includes several species of reptiles, which have become so overgrown in parts of the United States that most people assume they are native! And because of this, relatively little is done to control their populations – leaving them free to damage native ecosystems.

This article hopes to shed some light on these invasive herpes – because who knows, you might come across it every day without realizing it!

brown anole

invasive anole

If you’ve ever lived in or even just visited the southeastern United States, you’ve probably seen an anole before. Long-tailed, narrow-bodied, and nearly conical-headed, these little tree-dwelling lizards are pretty much everywhere you look, frequently scurrying up trees and along buildings.

The green anole is native and widespread in the southeast and is vital parts of many food webs. However, their numbers have dwindled considerably in recent years – and that’s largely thanks to these guys.

Brown anoles – identifiable by their exclusively brown and gray coloring – are native to the Caribbean, particularly on islands like Cuba and the Bahamas, but were introduced to North America over a century ago, likely by ships humans.

Since then, their numbers have exploded and expanded to cover much of the southern United States, displacing many native lizard populations.

Because they are larger and more adaptable, brown anoles tend to outperform their green anole cousins in all the environments they share – not helped by their penchant for eating the eggs of other anoles or the variety of non-native diseases and parasites they brought with them – which have greatly affected native populations and can have serious consequences in the future.

house gecko

Another (group of) invasive lizard that is currently making its rounds in the southern United States is the house gecko. This includes a variety of subspecies, including the common house gecko native to Southeast Asia and the Mediterranean house gecko native to the Mediterranean.

Geckos are fairly easy to tell apart in most cases: bulbous toes, large staring eyes (they’re well known for the lack of eyelids!) and even larger triangle-shaped heads.

House geckos like these are actually one of the most widespread and invasive species of lizards in the world, found far beyond their native range – from Florida to California.

This is facilitated in large part by their wide diet, rapid reproduction and popularity in the pet trade – like many popular pet reptiles, geckos are often released into the wild by unwilling owners. more.

This makes them an environmental concern, as they often displace native lizard species due to their numbers and competition for food.

red-eared slider

invasive cursor

Arguably one of the most invasive reptiles in the world, populations of these turtles can be found on every continent (except Antarctica of course) and in every US state.

red-eared sliders Easily identified by their colorful green and yellow striped patterns and named for the bright red spots behind their eyes, the red-eared slider or terrapin is native to the Midwestern United States, particularly around the Mississippi River and its many tributaries.

However, like house geckos, they have managed to spread well beyond this range through the pet trade.

Their striking appearance and docile temperament have made them the most popular pet turtle in the world. Unfortunately, many owners fail to realize the commitment they come with due to their large adult size and long lifespan, leading many to discard them in the wild.

Their exceptionally hardy nature allows them to survive and thrive in just about any environment, from Texas to New York, and even Hawaii! In fact, they are becoming dangerously overpopulated in many ecosystems, overwhelming native species and causing significant environmental damage.

brown tree snake

A less common, but even more destructive invasive species in the United States is the brown tree snake.

As the name suggests, these tree snakes come in shades of light brown and brownish yellow, often with dark bands running through their particularly long and slender bodies. They have a large, recognizable head and large eyes with catlike pupils.

Native to Southeast Asian islands like New Guinea, Australia, and Indonesia, this species has since spread across the Pacific to many other islands, such as Saipan and Guam.

They are particularly infamous in Guam because upon their arrival, with no natural predators and an extremely wide carnivorous diet, they were able to reproduce rapidly and wipe out many native fauna – more than half of the native species of birds, bats and lizards have since disappeared!

With the loss of these species, many of which were important pollinators on the island, a cascading effect occurred in Guam’s ecosystems, beginning with the reduction of native plant species that depended on these pollinators and leading to the loss and endangerment of many others.

The impact of this fairly inconspicuous reptile on an entire ecosystem is a great example of how harmful invasive species can be, and makes the potential spread of the brown tree snake further afield in places like Hawaii or even the continental United States is a serious concern.

water snakes

With lessons learned from the brown tree snake crisis in Guam, we should be on high alert for equally unique invasive reptiles – such as water snakes.

While water snakes can be found in many places around the world, there are 2 specific species that have become notoriously invasive.

Common and banded water snakes are recognizable by the spotted or banded patterns running down their thick, fairly heavy bodies in a variety of brown, gray, and red colors. They have relatively small, triangular heads, and their appearance often causes them to be mistaken for cotton-mouth/water-mouth moccasins.

Both of these species are native to the east coast of the United States, but in recent years populations have also begun to be found in the west, particularly in California.

This is a serious concern, because like the specialized brown tree snakes in Guam, California has no native water snakes other than garter snakes – meaning that more specialized water snakes are able to significantly outcompete native species and damage local ecosystems.

Already, these snakes are becoming a common site in California wetlands, and many populations of native species are also in decline.


As our world becomes increasingly interconnected, it becomes easier for some species to spread far beyond their native range and become invasive.

Invasive species pose an increasingly serious threat to the natural world. They often breed quickly in new environments and lack natural predators, allowing them to outnumber and outnumber native species.

This can quickly upset the delicate balance of many ecosystems, leading to loss of important species and environmental destruction.

Unfortunately, it is often incredibly difficult to determine where and how many invasive species there are. To combat this, it is important that ordinary people like us do our part and inform the competent authorities if we see one – something admittedly much easier said than done.

Some of the most invasive and damaging species are also the most secretive and in many cases are easily mistaken for something native. Here are some examples:

Originally from the Caribbean, these lizards have since spread across much of the southern United States and have outnumbered and drastically reduced populations of native lizard species like the Green Anole.

Many of these recognizable lizard species originating in the Old World made their way to the Americas and spread throughout the southern United States thanks in large part to the pet trade.

One of the most invasive reptiles in the world, their popularity as pets (and irresponsible misappropriation) has allowed these Midwestern native turtles to invade every continent on the planet in dangerously high numbers.

An infamous example of how dangerous invasive species are, these Southeast Asian natives are known to have wiped out most of Guam’s native bird, bat and lizard species – with the loss of pollinators resulting in a “domino effect” that severely reduced the island’s flora species and vegetation cover.

Native to the eastern United States, common and banded water snakes have been found in various California wetlands, alongside noticeably reduced native species populations in an uncanny similarity to Guam’s brown tree snakes.

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