caa a22 4500 605542732 CHVBK 20210128100923.0 cr unu---uuuuu 210128e20150301xx s 000 0 eng 10.1007/s10071-014-0823-3 doi (NATIONALLICENCE)springer-10.1007/s10071-014-0823-3 Why do seals have cones? Behavioural evidence for colour-blindness in harbour seals [Elektronische Daten] [Christine Scholtyssek, Almut Kelber, Guido Dehnhardt] 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-based) vision at light levels that lead to mesopic (rod-cone-based) vision in other mammals. This finding speaks against rod-cone-based colour vision in harbour seals. To test for colour-blindness, we used a cognitive approach involving a harbour seal trained to use a concept of same and different. We tested this seal with pairs of isoluminant stimuli that were either same or different in colour. If the seal had perceived colour, it would have responded to colour differences between stimuli. However, the seal responded with "same”, providing strong evidence for colour-blindness. The Author(s), 2014 Rod-cone-based colour vision nationallicence Colour-blindness nationallicence Spectral sensitivity nationallicence Marine mammals nationallicence Harbour seals nationallicence Scholtyssek Christine Lund Vision Group, Functional Zoology, Department of Biology, Lund University, Sölvegatan 35, 22362, Lund, Sweden aut Kelber Almut Lund Vision Group, Functional Zoology, Department of Biology, Lund University, Sölvegatan 35, 22362, Lund, Sweden aut Dehnhardt Guido Sensory and Cognitive Ecology, Institute for Biosciences, Rostock University, Albert-Einstein-Str. 3, 18059, Rostock, Germany aut Animal Cognition Springer Berlin Heidelberg 18/2(2015-03-01), 551-560 1435-9448 18:2<551 2015 18 10071 https://doi.org/10.1007/s10071-014-0823-3 text/html Onlinezugriff via DOI BK010053 XK010053 XK010000 Metadata rights reserved Springer special CC-BY-NC licence nationallicence 1 research-article jats NATIONALLICENCE NATIONALLICENCE NL-springer NATIONALLICENCE 856 40 https://doi.org/10.1007/s10071-014-0823-3 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Scholtyssek Christine Lund Vision Group, Functional Zoology, Department of Biology, Lund University, Sölvegatan 35, 22362, Lund, Sweden aut NATIONALLICENCE 700 1- Kelber Almut Lund Vision Group, Functional Zoology, Department of Biology, Lund University, Sölvegatan 35, 22362, Lund, Sweden aut NATIONALLICENCE 700 1- Dehnhardt Guido Sensory and Cognitive Ecology, Institute for Biosciences, Rostock University, Albert-Einstein-Str. 3, 18059, Rostock, Germany aut NATIONALLICENCE 773 0- Animal Cognition Springer Berlin Heidelberg 18/2(2015-03-01), 551-560 1435-9448 18:2<551 2015 18 10071