Predation techniques used by the Red Rock Crab Cancer productus on Marine Gastropods of varying shell length

Abstract

Relationships between shell thickness and predation techniques have been established; however, it has not yet been determined if a relationship exists between shell length and predation technique. Crabs often use a variety of techniques while trying to access their prey. Our study examines whether handling times and methods used to break open snail shells vary by shell length. We tested the red rock crab Cancer productus with various species and sizes of snails and observed methods used to access the snail’s flesh, timing each interaction. Total handling time increased exponentially with an increase in shell size. Larger snails were predominantly chipped at the aperture, while smaller snails were crushed outright. Crabs would occasionally break off the snail’s apex; however, this was rare. The results of this study may be used as a baseline for ocean acidification studies and also gives us a model for future behavioral studies related to predation.