Analysis of Learning of an Echolocation Task in a Bottlenose Dolphin

Abstract

Echolocation is one of the important senses in dolphins that contributes to their perception of the underwater environment. However, many questions still remain unanswered with respect to the development of their echolocation sense. It is observed that dolphins can be trained quite fast to perform an object recognition task. However, it is unknown whether dolphins have to learn to echolocate after birth or have the innate ability to do so. Here, an indirect approach of studying the acoustics in a non-neonate dolphin was conducted, to understand the development of echolocation in dolphins. A dolphin, named Angelo, was trained at a young age to perform several cross-modal matching tasks. These tasks involved echolocating an object concealed inside an anechoic box, followed by having to match it visually to the same object among several alternatives presented in air. The analysis of the learning curves associated with the dolphin’s progress showed that Angelo understood the concept of matching-to-sample. Along with the progress of the training, Angelo was observed to fine-tune some acoustic parameters in the clicks he transmitted. Both the average click number used by Angelo across trials and the variance of the mean frequencies of clicks in individual trials decreased as the training progressed. This fine-tuning of the acoustic parameters by Angelo suggested that there was learning of echolocation involved.