Despite the fact that most living organisms on Earth live peacefully and in perfect harmony with Mother Nature, there are some creatures that are absolute predators and in constant competition with other forms of life. According to most dictionaries, an invasive species is a plant or animal that is not native to a specific location. In other words, an introduced species that has a tendency to spread and is able to cause damage to the environment, the human economy, and human health. Some of these invasive creatures have caused the extinction of whole entire species and have irreparable damage to a surrounding ecosystem. With that said, don’t be fooled into thinking that these creatures are scary or even dangerous looking. Some of these creatures were actually kept as pets because they are so cute or even exotic. However, the sad reality is that when introduced into an environment where natural predators where not present, these animals got out of control and completely took over their respective areas. From the adorable looking gray squirrel to the frightening Burmese Python these are 25 Most Invasive Creatures On Earth. If you want to see animals who are destructively dangerous, check out the 25 most dangerous animals in the world.
American Comb Jelly
Commonly called the comb jelly or sea walnut, it is indigenous to temperate, subtropical estuaries along the Atlantic coast of North and South America. In the early 1980s, it was accidentally introduced via the ballast water of ships to the Black Sea, where it had a catastrophic effect on the entire ecosystem. In the last two decades of the twentieth century, it invaded the Azov, Marmara, and Aegean Seas and was recently introduced to the Caspian Sea via the ballast water of oil tankers.
The Nile Perch
The Nile perch is a large freshwater fish that can grow up to 200 kg and reach up to two meters in length. It was introduced to Lake Victoria in 1954, where it has contributed to the extinction of more than two hundred endemic fish species through predation and competition for food.
Believe it or not, the domesticated cat, which can be traced back three thousand years to the eastern Mediterranean, is one of the most invasive creatures on Earth. Considering the extent to which cats are valued as pets, it is not surprising that they have since been translocated by humans to almost all parts of the world. Notable predators, cats threaten native birdlife and other fauna, especially on islands where native species have evolved in relative isolation from predators.
The cannibal snail was introduced to Indian and Pacific Ocean islands from the 1950’s onward as a biological control agent for the giant African snail. As its name suggests, this snail will eat anything in its path, even its own kind.
Chinese Freshwater Edible Crab
Eriocheir sinensis (its scientific name) is a migrating crab that has invaded Europe and North America from Asia. During mass migrations it contributes to the temporary disappearance of native invertebrates. It modifies habitats by causing erosion due to its intensive burrowing activity and costs fisheries and aquaculture several hundred thousand dollars a year by consuming bait and trapped fish as well as by damaging gear.