True whelks are carnivores and scavengers. They feed on clams, carrion, and sometimes even on detritus. Their sense of smell is very well-developed; they can sense chemical signals from their prey from a considerable distance. Many whelks can bore through the shell of bivalves. Because of this, they can cause harm in oyster farms. Whelks can even attack fish caught in a net by extending their probosces to twice the length of their own bodies.