There are over 800 species of the marine snails known as whelks in the world and most are found in cold water. Tropical varieties also exist, but are generally smaller and more colorful than their coldwater counterparts.

The shells of whelks are generally elongated with a wide opening and are frequently incorrectly described as conchs. Whelks have complete shells even when they are in the larval stage. Unlike many other mollusks, whelks never go through a period when they can swim. Instead, the larvae simply crawl away from their egg capsules as fully formed, miniature whelks. Empty whelk shells remain strong for a long period of time and are often in demand by hermit crabs seeking a new home.

Whelks will eat many things and can smell prey from long distances. They are either scavengers or carnivorous and can aptly pry open shells of other animals, such as clams and oysters. Fishermen sometimes consider the whelk a pest since it can attack fish that are caught in nets by making a hole in their skin and eating the meat with its long proboscis. A whelk cannot, however, attack fish that are not dying or disabled from fleeing.