Hackles on tail!

[waterlocke22]

When my 5 month staff x plummer terriers hackles come up he also gets a 'ball' that comes right out all the way around about half way up his tail, is this normal?

[lankeela]

As Tom Jones would says, its not unusual! It is caused by a rush of adrenaline and is known as (honestly!) piloerection. Some dogs have hackles all over their body that rise, not necessarily from aggression, sometimes its fear or arousal when a female is in heat, or even just to make themselves look big in the face of another dog. Cats do a similar thing, they puff themselves up and it is often accompanied by a stiff tail and jumping in the air.