Are humans the only animal to experience vertigo?
David Muir
Edinburgh, UK
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Your vestibular system informs your brain about balance, movement and the physical location of your body parts in relation to your surroundings.
This complex set of structures and neural paths is situated in the inner ear. When something goes amiss within the vestibular system due to infection, trauma or drug intake (for instance, alcohol), you might experience vertigo, a sense of spinning and imbalance. Most vertebrates have vestibular systems, but not necessarily similar to that of humans, and various vestibular organs are present in invertebrates. Does this mean that many vertebrates, and even invertebrates, may suffer some kind of vertigo?
Vets describe symptoms of vestibular disease in pets, perhaps implying that they experience vertigo. These symptoms can include staggering, falling over, lack of coordination, head tilt and circling. However, we will need to wait for improved pet-human communications before we can know if this is truly vertigo.
These symptoms can also be exhibited by primates, elephants and me, after overindulgence in fermented fruit or the products thereof, thus compromising the vestibular system.
Mike Follows
Sutton Coldfield, West Midlands, UK
Experiments suggest that young mammals, including human infants, draw back from cliff edges. Thankfully, this is instinctive 鈥� and not learned behaviour 鈥� otherwise many individuals wouldn鈥檛 survive their mistakes. To show this, experimenters used a 鈥溾�� (a glass-floored bridge spanning a sheer drop), which mammals were reluctant to venture onto. Sea turtles had fewer qualms, probably because they experience swimming above drop-offs in the ocean with no ill effects.
Obviously, a few individuals suffer from acrophobia, the irrational fear of heights. Given our pampered lifestyle, it is possible that our species tolerates phobias better than other species do, perhaps because it might compromise their ability to compete for scarce resources.
Technically, vertigo is a spinning sensation in the absence of actual spinning, which can be triggered by movement, such as standing up or looking at a moving object.
Height vertigo can occur when looking down from a high vantage point or looking up at a tall object. A difference in pressure (or temperature) detected in the ears can also induce a spinning sensation.
Scuba divers can experience this if one ear clears before the other, particularly in chilly water. This can be particularly alarming out in the blue or in poor visibility when there is no visual reference.
Guy Cox
Sydney, Australia
Certainly not if we consider middle ear infections. Years ago, I got a phone call from my son saying that he had accidentally dropped his pet mouse and now it was paralysed. Well, you can drop a mouse from the Empire State Building and it stands a chance of walking away, so it was clear that something else was wrong. I headed home and we took the mouse to the vet. It was a middle ear infection, and the vet鈥檚 bill far exceeded the cost of the mouse!
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