Although humans are land mammals, we still occupy marine environments whether for work, leisure or exploration. But real sea mammals have adapted to living their entire lives in the ocean and the best adapted are whales and dolphins. Over time their adaptations have allowed them to live in a world with hardly any shelter where the sound is more important than sight. Being smart and able to cooperate plays a vital role in surviving in this kind of environment.
One thing we have in common with whales and dolphins is that we have big brains. How big? Without taking into account body size, sperm whales have the biggest brain in the world weighing around 7.8 kg. But in proportion to body size, humans have a bigger brain followed closely by dolphins; strangely enough, whales have a smaller brain than most seals.
We know that dolphins and killer whales have a much wrinklier cortex than humans, meaning it has a bigger surface area. However, does a bigger cortex mean more neurons? Even though we don’t know the exact number of neurons killer whales or dolphins have, researchers have counted the total number of neurons in the neocortex (part of the cortex) of the minke whale. Although it has a similar thickness to the human cortex, it only has 2/3 of the neurons we have. Even at the cellular level, we don’t yet know what these differences mean. Overall a thick cortex does not necessarily mean more neurons and a big brain does not necessarily mean more cognitive power. Taking into account different parameters, it’s hard to tell which animal is smarter.
However, putting aside our brains, it’s what we can do with them that is interesting. Amongst whales, dolphins, and humans, we all share behaviors that could be called culture. I say this carefully because the term culture can have different definitions and there is still debate on whether non-human animals can have culture in the way that we do. But let’s forget about humans—other animals have their own animal culture.
Similar to humans, some would argue that whales and dolphins have culture because they have the ability to communicate information with individuals of their own community. Even if whale/dolphin intelligence or culture does not correlate entirely with our definitions of such, the whole idea of trying to fit them into a human definition is somewhat absurd. Animals adapt to their environment and so, will develop strategies to overcome the hurdles their unique habitat presents; thus if a whale cannot invent the wheel maybe it’s because it doesn’t need to.