Resource guarding is when a dog is displaying aggressive behaviour (growling and/or biting) to protect their valued resource (food, bones, toys, items and sometimes significant other- dog or person).
This can be a very dangerous situation even though it is quite a natural behaviour and can range from fairly harmless to severe aggression.
Panos discusses some different variations of resource guarding, how it develops, how to maintain it but does not cover any remedy to this as advice on aggression over a podcast is not appropriate.
Seek professional help in person if you need to address this behaviour in your dog.

Ep150 - Resource Guarding 29:34 Share

Life With Your Dog