Stephen wrote
Roger Mills wrote

Have you tried this?
http://www.crocus.co.uk/product/_/to...id.2000004185/
[I haven't - but would be interested to know whether it actually works!]


Yes, I've seen recommendations for this on the internet but like all
the smelly approaches, the smell evaporates or is washed away by the
rain, so you have to keep applying it, which is expensive in the long
run. That's why I thought the ultrasonic or water approaches might be
better long term.

I only half understand the theory behind silent roar. I realise lions
are predators but surely not of cats? I wouldn't have thought the two
would have ever met in the wild for the one to know what the other
smells like.

That isnt necessarily how evolution works. Its likely just an accident that it works, if it works.