Is this the reason JK Rowling gave Hermione an otter patronus?

For Harry Potter fans, patronuses hold many secrets. From Professor Snape’s doe – which symbolised his love for Lily Potter – to Harry’s stag, to match that of his dad James, the shielding spell was often used to conceal hidden meanings.

But one character whose patronus has remained a mystery is Hermione. Cast your mind back to Harry’s sessions with Dumbledore’s Army and you’ll remember his best friend casting a patronus in the shape of an otter.

At the time, we didn’t think much of it – neither did we pay much heed to Ginny's horse, Luna's hare or Cho Chang's swan. But a scour of JK Rowling's Twitter feed suggests the author may have had special reason for equipping Hermione with an otter to fend off evil Dementors.

You see, she's rather a fan of them – as evidenced by this tweet:

And this one...

The author has also spoken in the past about how she identifies with the future Minister of Magic. "I have often said that Hermione is a bit like me when I was younger," she wrote on her website. "I think I was seen by other people as a right little know-it-all, but I hope that it is clear that underneath Hermione's swottiness there is a lot of insecurity and a great fear of failure (as shown by her Boggart in Prisoner of Azkaban)."

So, JK Rowling used her favourite animal as the patronus for the character she identifies with the most. Pretty neat, eh?