American Indians used smoke signals to alert others of multiple situations, including, to warn of danger, to call the people to a common meeting area and to transmit news. This ancient skill stems from the larger category of American Indian non-verbal communication. Different types of this, most notably sign language, were essential for American Indian communication. Since each tribe had their own unique language, these types of non-verbal signals enabled communication among diverse groups. This tool for transmitting messages was also extremely useful in mountainous or heavily forested regions