In researching brainless animals and while studying up on
worms for a second-grade classroom project, I came across some intriguing notes
regarding the brain situations of a few squishy creatures, all worth sharing!
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| photo by Pixabay user "blickwinkler" |
Earthworms
The part of a worm considered the brain lies above the throat,
sort of in the head like ours, and then connects to the first blob of neurons
in the worm’s body-length nerve cord.
That first neuron collection is called the first ventral ganglion – that
is, the first neuron cluster that doesn’t count as an official brain, located at
the belly / ground level of the worm.
The funky thing is this – if the worm’s brain is removed,
the worm never stops moving. If the
first ventral ganglion is removed, the worm forgets to dig or eat. So a worm can get on just fine for a while
sans brain, but would probably eventually exhaust itself.
So if you want to tell someone they have the brain of a
worm, you’re implying that they’re fairly versatile and can actually control themselves. And if you want to sound erudite when you do
it, say it like this: “Habes cerebrum vermis!” (or say it while waving a stick at someone
to come across as a serious Harry Potter fan.)
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| photo by István Asztalos |
Leeches
These squooshy, mostly water dwelling bloodsuckers are
actually full of brains! The leech’s
body is made up of 32+ segments, the front four serving as a head with a sucker
mouth and a leechy brain. Next come 21
segments, each with their own neuronal ganglia – basically a mini brain for
each segment. Finally, the last seven
sections make up the sucker tail and have a posterior brain directing traffic
from that end. You might say the leech
is a long, slinky bag of brains.
“Habetis cor hirudinea!” (“You have the brains of a leech!”…a
compliment, perhaps, or another really weird Hogwarts spell.)
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| photo by Pixabay user "Josch13" |
Caterpillars
Our last squiggly creature of brainy note is the
caterpillar, raised to worthy status as a mentally competent invertebrate by
virtue of its surprising capacity for memory.
Some intrepid researchers at Georgetown University conducted a study in which
they discovered that moths actually retained memories of things they had
learned as caterpillars. As with humans,
apparently, memories gained early in life faded before adulthood. But conditions present for the caterpillars
closer to their cocooning time appeared to be remembered after the larvae
emerged with wings.
This feat of memorization is impressive because, well
first of all, they’re squiggly creatures, but also because caterpillars
essentially liquefy in their cocoon and then coalesce into moth or butterfly
form. There’s a neat description of the
process by Scientific American here,
which kicks off the description of metamorphosis thusly: “First, the caterpillar digests itself, releasing
enzymes to dissolve all of its tissues.”
Ew! That those
caterpillars can retain memories through a process that’s even remotely like
that is totally amazing.
“Dare diploma a tinea!”
(“Give that moth a diploma!”…or as near
as I can get with Google Translate.)
“Ya’ll remember what to pick up at the store when you can
fly there, right?"
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| photo by Pixabay user "GLady" |
