Hi there, you are through to Dr Linda, a UK based vet with 10 years of clinical experience.
I'm sorry to hear that this has happened and understand how concerned you and your partner must be; I hope he is doing okay.
For some dogs, they will resource guard only when they have an item they perceive to be very high value, such as a bone or chew. If they sense we want to take away their 'treasure' they may start to react by giving warning signals like growling, snarling or lip curling. If we ignore these signals, this may escalate to snapping or even biting.
In the wild, this sort of behaviour is done so that a dog can ensure he doesn't go hungry or get bullied by other dogs. They are hard-wired to protect what is theirs and to not want to give up something of value.
When it comes to our pets, of course, it is not desirable for them to act this way.
Going forward, we can prevent this by:
- Not giving him access to any items that may trigger his guarding, such as bones or chews (Or only giving him these items when crated)
- Watching closely for body language that may signal he is going to get aggressive, and backing away from the situation
- Try to 'swap' the item he has by offering something extra tasty like hot chicken, so he chooses to give up items you do not want him to have
- Teaching a 'leave it' command to ensure he does not get access to things he should not
This link is quite good for this: