Hi! I'm Tim Tyler - and this is a video about how smart whales are -
in comparison with humans.
Humans often take pride in their large brains.
However, the human brain is relatively small in comparison to the
brains of elephants, dolphins and whales.
The largest brains known belong to female sperm whales - which are
fully six times more massive than the human brain.
Sperm whales look like this:
To give an indication of the size of their brains, here is a photograph
of John Lilly, next to a full-size model of the brain of a sperm whale:
Brain surface has valuable properties - and whale brains have more
convoluted surfaces - and a much larger surface area - than human
brains.
The number of neurons in the brain of a sperm whale has not yet been
measured - but based on calculations that extrapolate from the brains
of smaller whales, their neocortex is expected to have about 2.5 times
as many neurons as are found in humans.
A more interesting measure is the number of glial cells in the neocortex -
this is estimated to be 9 times as many as in the human brain.
Why so many glial cells? Whale brains have proportionally more white
matter than human brains, a sign of their sophistication. It seems
likely that the glial cells are there to support all the extra
metabolic activity.
Synapse numbers have not been measured directly - which is unfortunate
- since this figure would probably provide the best single estimate of
processing capability in whale brains.
Synapse numbers are known in Dolphins - and a crude
extrapolation to the Sperm whale suggests that they will have over
three times as many synapses as humans.
What about body size? It was once thought that the ratio of brain-size
to body size - the "Encephalization Quotient" - was more significant.
However, more recent findings cast doubt on this idea - suggesting
that absolute brain size is just about the single most important
factor in predicting cognitive ability from brain attributes.
So, we should be impressed at the enormous brains of Sperm whales.
Whales have complex social lives, and exhibit great behavioural
complexity. Carl Sagan had this to say about them:
[Carl Sagan footage]
The large whale brain is not terribly surprising once you consider
that it has been evolving in water for over fifty million years.
Unlike the human brain, whale brains do not have to fit through a
pelvis that also has to play an important structural role in walking.
Also, rather than being balanced on the top of a human spine, the
whale brain is supported and stabilised from all directions by
water.
As a result of all this, some whales have very large brains -
and they are probably much smarter than we are.
