Too nice to be invaders
Invasive species are often conceived of as the seven plagues: damaging insects, ugly amphibians and poisonous fish come to mind. But good-looking invaders are all around. What's worse: they're also continuing to spread.
50 shades of eastern grey
The eastern grey squirrel is native to some parts of North America, and was brought to Europe as a pet. They spread rapidly, displacing the native red squirrel, which is smaller and shyer. The eastern grey squirrel survives better in cold winters, and is destructive to European native trees, as it strips away the trees' bark to eat the sap below.
Not-so-innocent tea
Fennel is designed to invade - and not only your cups. It is a particularly aggressive herb, competing with native plants for light, nutrients and water. Fennel can expel substances that inhibit the growth of other plants, allowing it to grow dense and tall: up to 7 meters high.
Easter bunnies everywhere
Common rabbits were introduced to almost every continent long ago, and their breeding faculty allowed the species to spread like wildfire. Rabbits can harm plants, soil composition, and entire ecosystems. Australia and other islands, due to their lack of natural predators, have the most problems with these cute invaders.
Ninja turtles
Native to the southeastern United States, red-eared sliders were traded as pets. They have also spread rapidly into many parts of the world, and are among the invasive species with the most negative impact on biodiversity and the economy. Their rapid breeding and larger body size contribute to transmitting diseases to other turtles, with which they compete for food.
Red plague
Native to Europe, the red fox has successfully spread over America, Africa and Australia. As a predator, it acts as a keystone species in its natural habitat, controlling rodent populations. But in areas where it has been introduced - such as Australia, where it has no natural predators - it has become a destructive pest.
Too sweet to be true
Delicious raspberries are not easy neighbors. They tend to spread underground and colonize fertile soils, overtaking the growing space of native plants. Raspberry brambles can become very dense, limiting animals' access to water, while attracting invasive birds and rats.
I tawt I taw a puddy tat
Around 9,500 years ago, cats conquered humans and became the most popular pet in the world. This also helped them make their way into habitats where they don't belong. These felines are effective predators and hunt out of instinct even when not hungry, killing billions of birds per year. Cats are considered responsible for the extinction of more than 33 native species.
Invaders in the mirror
Humans can be seen as large, greedy mammals that seek wide range and consume vast amounts of resources. Known also as Homo sapiens, this species tends to overhunt with advanced techniques on land and water, causing the extinction of many other species. Their breeding rates and overuse of resources may even pose a danger for their own future.