Mantis shrimp rank the shape of an object over its color during recognition

Abstract

Mantis shrimp are predatory crustaceans that commonly occupy burrows in shallow, tropical waters worldwide. Most of these animals inhabit structurally complex, benthic environments with an abundance of visual features that are regularly observed, including conspecifics, predators, prey, and landmarks for use in navigation. While these animals are capable of learning and discriminating color and polarization, it is unknown what specific attributes of a visual object are important for its recognition. Here we show that mantis shrimp of the species Neogonodactylus oerstedii can learn the shape of a trained target. Furthermore, when the shape and color of a target which they had been trained to identify were placed in conflict, N. oerstedii significantly chose the target of the trained shape over the target of the trained color. Thus, we conclude that the shape of a target is more important than its color for its recognition by N. oerstedii. Our findings suggest that the shapes of learned structures, such as landmarks or other animals, are important for N. oerstedii during object recognition.