Why do seals have cones? Behavioural evidence for colour-blindness in harbour seals.

ABSTRACT: All seals and cetaceans have lost at least one of two ancestral cone classes and should therefore be colour-blind. Nevertheless, earlier studies showed that these marine mammals can discriminate colours and a colour vision mechanism has been proposed which contrasts signals from cones and rods. However, these earlier studies underestimated the brightness discrimination abilities of these animals, so that they could have discriminated colours using brightness only. Using a psychophysical discrimination experiment, we showed that a harbour seal can solve a colour discrimination task by means of brightness discrimination alone. Performing a series of experiments in which two harbour seals had to discriminate the brightness of colours, we also found strong evidence for purely scotopic (rod-bas

SUBMITTER: Scholtyssek C 

PROVIDER: S-EPMC4320766 | biostudies-literature | 2015 Mar

REPOSITORIES: biostudies-literature