Developing an Archerfish (Toxotes jaculatrix) Ethogram to Examine Self-Recognition and Mirror-Image Discrimination

Abstract

Self-recognition is a definitive aspect of consciousness, leading to several experiments testing it in a range of animal taxa. The most famous of these has been the mark test, which measures a subject’s ability to self-recognize by its engagement with a visual marker placed on its body and perceived through a handheld mirror. Instead this study used a mirror exposure task to test self-recognition, due to archerfish’s lack of forearm dexterity, thus preventing the fish from being able to touch a visual marker. During eight days of observations, four archerfish were monitored for possible mirror-directed behaviors, based on previous mark and mirror exposure research on cleaner wrasses and manta rays, respectively. This behavioral data was then organized into an ethogram, from which we found that the archerfish most frequently hover, whereas they chase each other or swim backward least often. After noting the number of fish on each side of the tank, the mirror’s position in each trial, and applying the Wilcoxon Signed Rank Test, we discovered that the fish had no preference for either the mirror or non-mirror side. Thus, it is inconclusive if the fish display any mirror self-recognition (MSR) and requires further research.