DOI: 10.5061/dryad.5mp83f1
title: Data from: Smashing mantis shrimp strategically impact shells

description: Many predators fracture strong mollusk shells, requiring specialized
 weaponry and behaviors. The current shell fracture paradigm is based on
 jaw- and claw-based predators that slowly apply forces (high impulse, low
 peak force). However, predators also strike shells with transient intense
 impacts (low impulse, high peak force). Toward the goal of incorporating
 impact fracture strategies into the prevailing paradigm, we measured how
 mantis shrimp (Neogonodactylus bredini) impact snail shells, tested
 whether they strike shells in different locations depending on prey shape
 (Nerita spp., Cenchritis muricatus, Cerithium spp.), and deployed a
 physical model (Ninjabot) to test the effectiveness of strike locations.
 We found that, contrary to their formidable reputation, mantis shrimp
 struck shells tens to hundreds of times while targeting distinct shell
 locations. They consistently struck the aperture of globular shells and
 changed from aperture to apex of high-spired shells. Ninjabot tests
 revealed that mantis shrimp avoid strike locations that cause little
 damage and that reaching the threshold for eating soft tissue is
 increasingly difficult as fracture progresses. Their ballistic strategy
 requires feed-forward control, relying on extensive pre-strike setup,
 unlike jaw- and claw-based strategies that can use real-time neural
 feedback when crushing. However, alongside this pre-processing cost to
 impact fracture comes the ability to circumvent gape limits and thus
 process larger prey. In sum, mantis shrimp target specific shell regions,
 alter their strategy depending on shell shape, and present a model system
 for studying the physics and materials of impact fracture in the context
 of the rich evolutionary history of predator-prey interactions.
description: Craneetal_2018_CerithiumApertureDamageCerithium spp. shells were either struck by Ninjabot 20 times or by mantis shrimp during feeding experiments. The quantity of damage caused to the aperture of each shell is reported here.Craneetal_2018_CerithiumApexDamageCerithium spp. shells were either struck by Ninjabot 20 times or by mantis shrimp during feeding experiments. Measurements of shell length and the damage caused to the apex of each shell are reported here.Craneetal_2018_FeedingTrialsInformation about every attempted feeding – experiments where one mantis shrimp was presented with one snail. Each row represents one attempted feeding.Craneetal_2018_MantisShrimpSizeMantis shrimp body length and carapace length were each measured three times after every molt.Craneetal_2018_NinjabotTrialsNinjabot, a physical model of the mantis shrimp strike, hammered snail shells in different locations. Each row corresponds to a single shell that was struck multiple times by Ninjabot.Craneetal_2018_ShellSurfaceAreaThe projected surface area of each snail shell region was measured on representative undamaged shells of each shape. Measurements are compiled from a dorsal and ventral photograph of each snail.Craneetal_2018_SnailSizeShell length was measured three times for each snail before it was fed to a mantis shrimp in the feeding experiments.Craneetal_2018_StrikeLocationsMantis shrimp were presented with a snail. For every feeding where the mantis shrimp ultimately consumed the snail, the timing and location of every strike were recorded. Every row represents a single strike from a single strike sequence.Craneetal_2018_FiguresandAnalysesR script to produce all figures and analyses.