I don’t know about you, but often I’ll randomly stumble onto an intriguing question that I can’t even possibly imagine the answer to. Unfortunately I always seem to do this when I don’t have a pen or computer, and invariably I always forget the question by the time I have the ability to look it up. But ‘lo, I have restumbled onto an old, previously forgotten question!
We all know (at least I hope) that sharks breathe using ram-ventilation. That is, they breathe by swimming forward, and their gills extract the oxygen out of the seawater as it passes over them. Which begs the question, if a shark can’t stop moving, how does it sleep? The short answer is, we don’t know. However the most likely theories, which vary depending on the type of shark, are pretty fucking amazing.
- Some sharks can sit on the ocean floor and pump water over their gills. But their eyes are open and will follow the movement of divers or fish.
- Some sharks’ spinal cords, rather than their brains, coordinate movement. This means that a shark could sleep and swim at the same time.
- Some sharks may sleep the way dolphins do, by shutting down one hemisphere of their brain at a time. This allows the shark to literally be half-concious.
- And last but not least, analysis of some sharks brainwaves indicate that they may experience something similar to somnambulism, which means sleepwalking.
Man, that’s awesome.
February 19, 2008, 12:08pm
