Squid have some of the thickest nerve fibers of any animal. They help the squid zoom away from danger, and they taught scientists how nerves work!
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Nerve cells send messages around an animal's body. Each one has a long wire called an axon that carries the message. You can read about yours on the Nerve cells page.
Most axons are much too thin to see. But a squid has a giant axon that can be up to about 1 millimeter thick. That is thick enough to see with just your eyes!
The giant axon does not come from a giant squid. It is found in ordinary squid that are about the size of your arm or smaller.
A squid's body is a muscly tube called the mantle. To escape danger, the squid squeezes its mantle hard and shoots water out of a nozzle called the funnel. Whoosh! It jets away.
Thicker nerve wires carry messages faster. The giant nerves send the "squeeze now!" message to the whole mantle at almost the same time, so all the muscles squeeze together.
Scroll up to the 3D model. Press Send a message, then press Jet away!
Blow up a balloon and let it go (in a safe, open space). The air rushing out pushes it forward, just like water rushing out pushes a squid!
Because the giant axon is so big, scientists could put tiny wires inside it. They measured the electric signal as a message zoomed along.
They found that nerve messages are made by tiny bits of salt moving in and out of the axon. Your nerves work the same way! Two scientists, Alan Hodgkin and Andrew Huxley, won a Nobel Prize for this work.
Much of what we know about how your brain and nerves send messages started with studying a squid!