FT263


The myth

Because the number one killer of hedgehogs today is the motorcar, the animal is evolving out of its old habit of rolling up into a spiny ball in the face of danger. Natural selection is killing off the “roll up” gene, and favouring the “run like hell” gene.


The “truth”

No one seems to know where this superficially sensible-sounding, but completely unsupported, hypothesis began. The world’s number one expert on the European hedgehog, Pat Morris, writes of having first heard it in the mid-1970s, and says that it was given a boost in 1995, when it was used in a GCSE exam paper. We can call it a mythconception simply because there isn’t a shred of evidence to suggest it’s true – but more than that, Morris and others have pointed out that it’s based on a fallacy. A stationery hog is only in danger from a car if it’s in line with the wheels; an animal running across the path of the vehicle is more likely to come into line with the wheels, while one running in a straight line is in no more or less danger than it would be if it stayed still. So rolling up is, mathematically, a better strategy than running.


Sources

The new hedgehog book by Pat Morris (Whittet Books, 2006); A prickly affair by Hugh Warwick (Allen Lane, 2008).


Disclaimer

There’s no evidence for it, and its reasoning is flawed – but of course that doesn’t necessarily mean it’s not happening. If you have proof either way, please roll it up and send it to FT’s letters page.