Culturas are an alien species.
They got there name because the look like the "normal" pop cultural alien (little, green, and their species have big heads)(so Culturas seemed like a fitting name).
They are unlikely to attack unless provoked.
There have been few sigtings but we fear it's feared that it won't stay that way. Because every goverment that has sighted one of them has decided to take them and disect them (AKA provoking them).