View full lesson: http://ed.ted.com/lessons/why-are-blue-whales-so-enormous-asha-de-vos

Blue whales are the largest animals on the planet, but what helps them grow to the length of a basketball court? Asha de Vos explains why the size of krill make them the ideal food for the blue whale -- it's as if the blue whale was made to eat krill (and krill was made to be eaten by the blue whale).

Lesson by Asha De Vos, animation by Cognitive Media.