Just wanted to give a quick round-up of the recent, intriguing discussion of the (potential) driving mechanism and the function of the eyes of giant squid. If you haven’t seen the paper that started it all you should most definitely read Nilsson et al.’s paper in Current Biology, a piece that introduced a new powerful model of vision in the deep-sea, along with the thought-provoking hypothesis that sperm whale predation may be the driver of eye size evolution. We followed up with a study in which we presented data on the scaling of eye size in squid, which indicated that giant squid have giant eyes because they are giant. The discussion of the implications of the visual modeling and the analysis of relative eye size continued in a pair of short papers published in the last couple months. All in all, this series of papers provides an interesting example of comparative biology, including optical modeling, functional morphology, scaling, and adaptation (or exaptation)? Take a look.
Nilsson D-E, Warrant EJ, Johnsen S, Hanlon R, Shashar N: A unique advantage for giant eyes in giant squid. Curr Biol 2012, 22:1–6.
Schmitz L, Motani R, Oufiero CE, Martin CH, McGee MD, Gamarra AR, Lee JJ,Wainwright PC: Allometry indicates that giant eyes of giant squid are not exceptional. BMC Evol Biol 2013,13:45.
Nilsson D-E, Warrant EJ, Johnsen S, Hanlon R, Shashar N: The giant eyes of giant squid are indeed unexpectedly large, but not if used for spotting sperm whales. BMC Evol Biol 2013, 13:187.
Schmitz L, Motani R, Oufiero CE, Martin CH, McGee MD, Wainwright PC: Potential enhanced ability of giant squid to detect sperm whales is an exaptation tied to their large body size. BMC Evolutionary Biology 2013, 13:226.
We hope that the field continues to investigate these questions.