BHWW This is leftover behavior from the ancestors of the Shiba Inu, which were originally bred to flush out and hunt the now extinct, vicious, feral cabbages that once roamed across Japan in great numbers.
RedHood You forgot to mention the cabbages were also Demons who possesed super natural abilities.
fluffy At night they would grow long tendrils with which they became ambulatory so that they could rape the village women.
CJH It's true, adorable babies were once found in heads of cabbage, whole patches of them, until the merciless Inus developed a taste for that sweet mixture of lettuce and childflesh.