[VadeRetro]

What is the evolutionary explanation. The text at the source says "He is reported to have a 4in 'tail' caused by genetic mutations during the development of the foetus."

Just a wild guess from a B.S. in Psychology, 1972: the mutation turned on his existing tail vertebrae genes. Do you know you have the gene to synthesize vitamin C but it's disabled by another slice of genetic code somewhere?

[VadeRetro]

1972

1971. I wasn't trying to seem younger, honest!

[AndrewC]

Just a wild guess from a B.S. in Psychology, 1972:

I mistook "from a" for "from the" and froze for a second.

That's a joke, just a joke :^)