ナショナルジオグラフィックさんのインスタグラム動画 - (ナショナルジオグラフィックInstagram)「Video by @bertiegregory / For such a large animal, the basking shark's eyes aren’t very big. It’s thought that their eyesight isn’t needed to detect plankton, and just used to dodge strange objects (like me!) and to determine the light level. Just behind the eyes is the brain. Poet Norman MacCaig described basking sharks as "That room-sized monster with a matchbox brain." Despite being able to grow to more than 10m/30ft, their brains are only about 10cm long. Unlike their great white cousins, which actively and strategically hunt fast-moving prey, it’s thought that basking sharks’ evolutionary needs don’t include a big brain: plankton doesn’t exactly run away. Basking sharks also can’t afford the energy required for a large brain, as their prey isn’t energy-rich seals. So if they’ve got bad eyesight and a tiny brain, how do they find their food? Well, smell is the secret weapon. In fact, their nerval mass for smell is actually bigger than their brain. Follow @bertiegregory for more wildlife adventures! #britishwildlife #underwater #freediving #baskingshark #shark #scotland」11月28日 20時43分