Species invasions are actually a very common occurrence on a global scale. Although there are countless species of organisms on the planet, these are distributed all over the world, with some species being endemic to certain areas and not present in others, and others having a relatively wide distribution. When some species appear in places where they would not have previously existed, this is when the species may become invasive.

The world's largest frogs are carnivores, but when these giant frogs were tadpoles, they were super picky eaters and only ate a water plant that was a specialty of local waters

Water bears are the common name for retarded animals, and these creatures are so small that their body length is usually no more than 1 mm, so we usually do not notice their presence.