Canine warnings are vocalizations that dogs use to communicate with other animals and humans. Snarls, which are six letters long, are a type of warning that is a low, threatening growl. Grrs, which are four letters long, are a type of warning that is a short, sharp bark. GISTS, which are five letters long, are a type of warning that is a high-pitched yelp. All of these canine warnings are used to express displeasure or to warn of potential danger.