Howling Shiba Inu

[SYbex7254]

We have 2 Shibas, a 12 year old male and a 11 year old female. Both are very active and healthy (recently got a clean bill of health from our vet). Both are also crate trained since they were puppies and are free to roam our downstairs when we are home but are crated when we are either at work or at night when we go to bed. Out of the blue the female recently started howling at night - at times for hours on end - and is causing both my wife and I a great deal of lost sleep.

This has been going on since Thanksgiving timeframe and neither one of us can identify anything to cause this (no changes to anything in their environment - it's like someone turned on a howling switch) other than the fact she no longer wants to be in the crate at night. We've tried a No-Bark collar (3 of them actually) and they have been less than 50% effective at best. I've given her toys and chews at night too and it hasn't curtailed the issue. I have thought about allowing her to remain outside of the crate at night but fear that doing so will be allowing her to "win" and cause potential issues between her and the male. I might add that she thinks she's the Alpha Dog and as most who have had Shiba's know, they are a very strong minded breed.

So the question I pose to the group is does anyone have any suggestions for resolutions or have had similar experiences? From searching on the internet I see potential causes to be Separation Anxiety - which I could understand BUT the dog has been doing the same routine for all of her 11 years.

I welcome any suggestions or recommendations...