Predation by drilling gastropods is preservable in the fossil record and thus provides valuable examples for the study of evolutionary concepts that emphasize the importance of biotic interactions. For cost-benefit analyses, accurate measurement of drilling rate and consumption rate is essential. We experimentally determined the drilling, excavation, and consumption rates of the muricid gastropod Nucella lamellosa preying upon the mussel Mytilus trossulus. Our results indicate that although drilling rate is independent of predator size, excavation rate is proportional to the size of the driller, as one might expect on biomechanical grounds. In addition, consumption rate is also a function of predator size, which might have important implications in cost-benefit analyses applied to varied-sized predators, as we illustrate with an example.