If humans possessed a tail, what could they have done with it?
One of my anatomy books contains a photograph of a boy with a tail the length of a little finger. Humans with tails are exceptionally rare and only a few dozen have been reported worldwide. Normally humans, just like frogs or the great apes, are tailless. The only frogs that have tail-moving muscles (but no tails to move them with) are the secretive Leiopelmatidae of New Zealand and the rare Rocky Mountain species Ascaphus.
Human beings usually possesses 4-5 rudimentary vertebrae at the end of the vertebral column, known as the coccyx. In the great apes, there is anatomically even less that could be interpreted as the remnant of a tail, because the coccyx consists of no more than three miniscule bony leftovers of an ancestral tail.
But let’s imagine for a moment we all had a tail: what could we do with it? We could chase away flies or use it as a fan on hot days. On cold nights we might use it as a kind of blanket to cover ourselves just like squirrels do. Or we could defend ourselves with it like a porcupine and carry out tail fights similar to those of lizard combattants and ancient dinosaurs would have engaged in. We might be able to use our tails for making noises (the rattle snake comes to mind) or, like beavers, could carry our offspring around on our tails. Like circus elephants instead of holding hands we could hold tails. A tail would be an extremely useful appendage during gymnastic and climbing exercises as so many monkeys, arboreal anteaters, rodents, pangolins, to name but a few; demonstrate so aptly. Some South American monkeys are so well adapted to a life amongst the branches of the tropical trees that even a dead monkey can hang by its tail and not fall to the ground! A tail could be a useful device to warn other individuals of the approach of danger (deer are communicating with each other in this way) and it could also be an indicator of one’s mood and frame of mind as in dogs and wolves. It could be an eye-catching ornament, especially when colourful, and thus an attribute of femininity (or masculinity), just as it is amongst our feathered friends. Last but not least, a powerful tail could change swimming competitions forever.
What we learn from this little thought-provoking exercise is that shape, size, and development of a tail are the evolutionary results of the functions it has been put to – and as we’ve seen the latter are numerous. Although it is certain that the tail of a whale, known as the fluke, is not simply a modification of the hind legs of its terrestrial ancestors, the history of the tail of a whale is such a whale of a tale that I had better curtail my story here.
© Dr V.B. Meyer-Rochow and http://www.bioforthebiobuff.wordpress.com, 2015.
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