4) The Vagus Nerve
The vagus nerve is still an integral part of the wiring in a human (and many other animals), but the path of one of its offshoots — the laryngeal nerve – tells us a little story about how we evolved.
Fish still have the equivalent nerve which runs from their brain to their larynx in an efficient, direct route. However, as creatures evolved and other structures got in the way the laryngeal nerve was sent somewhat out of its way. The nerve now has to find its way round the heart’s aorta sending it inches in the wrong direction. That doesn’t seem particularly wild, but this is taken to literally ridiculous lengths in the giraffe where the nerve has to travel a full 15 feet out of its way to get from the brain to the larynx. Woops.
