Key 21,
Strangely Incomprehensible Just when we think we understand the world and how it works,
Something can come along to turn our ideas of how things work on their head.
The seahorse demonstrates this admirably,
Being odd in two respects.
Firstly,
As it swims upright,
While virtually all other fish swim horizontally.
Only the razorfish swims in a similar fashion.
The second strange thing about seahorses is how they reproduce.
They court for several days.
During this time they change colour,
Swim side by side,
Holding tails and gripping the same strand of seagrass.
They often wheel around in unison,
In a dance which can last up to eight hours.
During this dance,
The male pumps water through the egg pouch on his trunk,
Which expands and opens to display its emptiness.
The female inserts her ovipositor into the male's brood pouch and deposits thousands of eggs.
As the female releases her eggs,
Her body slims while his swells.
Both animals then sink back into the seagrass and she swims away.
Nobody knows quite what the female seahorse does after leaving the male to hold the babies.
She is obviously a mistress of her elements.
The Latin name for seahorse is hippocampus,
Which comes from hippo meaning horse,
And campus meaning sea monster.
Some of them are over 14 inches in height and very dragon-like.
Inside our heads are two seahorse-shaped structures,
One on each side of the brain,
Also called the hippocampus.
It is perhaps strangely coincidental that the role of the hippocampus seems to be to help us make sense of the world.
It even lights up when it detects something out of the ordinary.
It encodes and makes sense of memories,
And creates a navigational map of the world.
This is not necessarily a physical atlas.
It is a map of how the world works and how we fit into it.
Dementia sets in when this part of the brain degenerates.
Just by listening to these words,
The two oddities about aquatic hippocampi have holographically been mirrored inside your own hippocampi.
Now that is strangely incomprehensible.