Why guinea pigs?

Why guinea pigs?
I've heard innumerable times: They're for children.
And: I had one when I was a kid. It didn't last long - it died.

I have a couple of guinea pigs and out of interest started reading about them on the Internet. Soon I read the same three ideas on how the name of "guinea pig" came into being. I thought surely someone knows the definitive answer?

I'm a librarian and I thought - I'll do a bit of research and find out for myself, and answer the question.

A couple of years later, and I haven't got any further to finding the answer to why they're called guinea pigs.

The journey has been fascinating - taking me to South America pre-Spanish conquest, to Elizabethan England, to the Renaissance in Europe, to Peter Paul Rubens and Jan Brueghel in Antwerp, to Conrad Gessner's history of the quadrapeds and to the Library of Congress in Washington DC in the United States and to the British Library in London, England.

Now I'm back in Brisbane - and still researching.