Mesozooplankton are a size group of zooplankton (0.2 mm to 2 cm) that is often lumped together with smaller, microzooplankton taxa, and treated as a functionally homogeneous group in oceanic surveys and biogeochemical models. Di Matteo used a trait-based modeling approach that accounts for the strong functional differences among mesozooplankton taxa, here grouped as cruisers, ambushers, and flux-feeders. Integration of model results with observational data revealed clear biogeographical distribution patterns that suggest distinct roles of major mesozooplankton groups with respect to their contributions to oceanic food webs and the export of carbon to the deep ocean.