The giant eyes of giant squid are indeed unexpectedly large, but not if used for spotting sperm whales

BMC Evolutionary Biology

Nadav Shashar¹  Roger T Hanlon⁴  Sönke Johnsen²  Eric J Warrant³  Dan-E Nilsson³ 

[1] Department of Life Sciences, Eilat Campus, Ben Gurion University of the Negev, Eilat 88000, Israel;Biology Department, Duke University, Durham, NC 27708, USA;Department of Biology, Lund University, Lund 22362, Sweden;Marine Biological Laboratory, Woods Hole, MA 02543, USA

关键词: Mesopelagic;    Bioluminescence;    Sperm whale;    Giant squid;    Eyes;    Vision;   

Others  :  1086404
DOI  :  10.1186/1471-2148-13-187

 received in 2013-07-10, accepted in 2013-09-03,  发布年份 2013

【 摘 要 】

Background

We recently reported (Curr Biol 22:683–688, 2012) that the eyes of giant and colossal squid can grow to three times the diameter of the eyes of any other animal, including large fishes and whales. As an explanation to this extreme absolute eye size, we developed a theory for visual performance in aquatic habitats, leading to the conclusion that the huge eyes of giant and colossal squid are uniquely suited for detection of sperm whales, which are important squid-predators in the depths where these squid live. A paper in this journal by Schmitz et al. (BMC Evol Biol 13:45, 2013) refutes our conclusions on the basis of two claims: (1) using allometric data they argue that the eyes of giant and colossal squid are not unexpectedly large for the size of the squid, and (2) a revision of the values used for modelling indicates that large eyes are not better for detection of approaching sperm whales than they are for any other task.

Results and conclusions

We agree with Schmitz et al. that their revised values for intensity and abundance of planktonic bioluminescence may be more realistic, or at least more appropriately conservative, but argue that their conclusions are incorrect because they have not considered some of the main arguments put forward in our paper. We also present new modelling to demonstrate that our conclusions remain robust, even with the revised input values suggested by Schmitz et al.

【 授权许可】

   
2013 Nilsson et al.; licensee BioMed Central Ltd.

【 图 表 】

Figure 1.

【 参考文献 】

• [1]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. BioMed Central Full Text
• [2]Nilsson D-E, Warrant EJ, Johnsen S, Hanlon R, Shashar N: A Unique Advantage for Giant Eyes in Giant Squid. Curr Biol 2012, 22:683-688.
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