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.

When we humans feel very tired, we often say that we can fall asleep standing up, but this is just a description. In reality, it is impossible for humans to sleep standing up, but there are many animals in nature that have this such a skill that humans do not have, for example, horses can sleep standing up effortlessly.

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.