Whale Brains

Ever since I watched Keiko jump over Jesse at the emotional finale of ‘Free Willy’, as a wee lad, I have always felt a deep emotional connection with cetaceans. That’s why I thought it would be appropriate that my first blog post pose the question, “What is the best way to find out how smart are marine mammals?”.

Whales have recently been brought back into the media’s attention, with Australia’s attempt to prevent Japan from continued whaling [Guardian]. Also quite coincidently, I happen to be starting two books, Death At SeaWorld and Are Dolphins Really Smart?, both of which at their heart examine how we perceive whales and dolphins. So, most likely this will take the theme for a couple more blog posts after this one, as each book will get reviewed by Brian and I at a later date.

Cetaceans (whales, dolphins or porpoises) have very large and complex brains, which most often thanks to evolution equates to advanced behaviour, such as the development of culture [Nat Geo] or of being able to recognise themselves [Reiss & Morino, 2001). It is very hard to simply measure one animal against another and compare how ‘smart’ they are, because intelligence is a human centric concept and not a scientifically measurable term. One way to help understand what cetaceans might be capable of, includes understanding how their neural system functions or more simply what their brain is made of.

The measure of a whale is a great post that talks about not only how big their brains are in relation to their body, but also how long their nerves have to be in order to process information. While the size of the brain can sometimes be important for “intelligence”, a far more commonly used and statistically significant factor is the brain to body size ratio. For example, the brain of a Sperm whale weighs approximately 8kg, whereas a humans may be 1.5kg. Yet, when you consider the ratio of it in comparison to the size of the body, for the whales it is 0.02% and 2% for us. Size however, is one of many factors to be considered. The numbers and types of nerve cells that make up the brain (neurons) are also very important to consider [Are Whales Smarter Than We Are].

More specifically, there is the Von Economo neuron, a type of nerve cell in the brain, which was recently found not only to be found in humans and apes, but in a range of species including cetaceans and elephants. It is believed the presence of this neuron allow for the development of “complex cognitive and social/emotion processes” [Butti et al., 2009]. But does this mean that whales have the ability to feel emotion? Well, this image below from [Marino et al., 2007] showing two sections from the brains of A-Bottle Nosed Dolphin and B-Humpback Whale in addition to cell counts from [Eriksen & Pakkenberg, 2007], reveals that the cetacean brain is a very complex structure. Together this information helps us indicate that they may be able to process large volumes of data, which is needed for complex behavior or emotion, etc.  Ok, so now we know how complicated their brains can be, how did they get like that?

cetancean_brains

Well, from here we head briefly into the world of genetics. A nice review, Same gene linked to bigger brains of dolphins and primates covers the past few years of discovery, revealing that while some genes involved in neural development in primates are not the same as those in cetaceans [McGowen et al., 2011], some are [Xu et al,. 2012]/[McGowen et al., 2012]. These genes have been found to be connected to genetic disorders in humans, where it can make a brain smaller than it should be. As a brief aside, if you are interested in more genetic evolutionary cool stuff, check out this post on Convergent evolution in whale and bats. Anyway, now it is important for us to understand when these genetic changes may have kicked in to create such a well developed noggin’.

It is very important to understand when in history these changes may have arisen, because that may help us understand the why. There are a number of theories that try to explain it, but [Marion et al., 2004] found that there were in fact at least two periods of growth. From here, we could surmise that the development of more complex behaviors such as echolocation or communication may be the cause. A more contentious hypothesis by [Manger, 2007] creates the idea that the increase of brain size helps to counteract the amount of heat that would be lost by such large underwater animals. This one has received a lot of attention (not all good) in the literature though, if you are interested in following it up.

It is challenging for us really comprehend how ‘smart’ another species is, partly because we often unintentionally anthropomorphically analyse them, which is not scientifically acceptable. In this short piece I have not discussed why the evidence for their ability to teach one another [Bender et al., 2008], to play [Deakos et al., 2010] or to provide care [Gero et al., 2009] warrants them a rung on the intelligent species ladder. But maybe that is a good thing, because by looking only at the biological construct of cetaceans that may allow for these complex behaviors and not the behaviours themselves, you remove the presence of anthropomorphism. Then finally you might be able to construct a solid argument for why these creatures should be protected.

Related links;

The science of animal consciousness

When Animals Mourn

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